diff --git a/CMakeLists_files.cmake b/CMakeLists_files.cmake
index 2c72586f11..f121238f37 100644
--- a/CMakeLists_files.cmake
+++ b/CMakeLists_files.cmake
@@ -225,7 +225,6 @@ list (APPEND MAIN_SOURCE_FILES
   opm/simulators/wells/GroupEconomicLimitsChecker.cpp
   opm/simulators/wells/GroupState.cpp
   opm/simulators/wells/GroupStateHelper.cpp
-  opm/simulators/wells/GroupTargetCalculator.cpp
   opm/simulators/wells/MSWellHelpers.cpp
   opm/simulators/wells/MultisegmentWellAssemble.cpp
   opm/simulators/wells/MultisegmentWellEquations.cpp
@@ -1169,7 +1168,6 @@ list (APPEND PUBLIC_HEADER_FILES
   opm/simulators/wells/GroupEconomicLimitsChecker.hpp
   opm/simulators/wells/GroupState.hpp
   opm/simulators/wells/GroupStateHelper.hpp
-  opm/simulators/wells/GroupTargetCalculator.hpp
   opm/simulators/wells/GuideRateHandler.hpp
   opm/simulators/wells/MSWellHelpers.hpp
   opm/simulators/wells/MultisegmentWell.hpp
@@ -1379,6 +1377,7 @@ if(MPI_FOUND)
     opm/simulators/flow/rescoup/ReservoirCouplingSlaveReportStep.cpp
     opm/simulators/flow/rescoup/ReservoirCouplingSpawnSlaves.cpp
     opm/simulators/flow/rescoup/ReservoirCouplingTimeStepper.cpp
+    opm/simulators/wells/GroupTargetCalculator.cpp
     opm/simulators/wells/rescoup/RescoupReceiveGroupTargets.cpp
     opm/simulators/wells/rescoup/RescoupReceiveSlaveGroupData.cpp
     opm/simulators/wells/rescoup/RescoupSendSlaveGroupData.cpp
@@ -1395,6 +1394,7 @@ if(MPI_FOUND)
     opm/simulators/flow/rescoup/ReservoirCouplingSlaveReportStep.hpp
     opm/simulators/flow/rescoup/ReservoirCouplingSpawnSlaves.hpp
     opm/simulators/flow/rescoup/ReservoirCouplingTimeStepper.hpp
+    opm/simulators/wells/GroupTargetCalculator.hpp
     opm/simulators/wells/rescoup/RescoupProxy.hpp
     opm/simulators/wells/rescoup/RescoupReceiveSlaveGroupData.hpp
     opm/simulators/wells/rescoup/RescoupReceiveGroupTargets.hpp
diff --git a/opm/simulators/wells/BlackoilWellModel_impl.hpp b/opm/simulators/wells/BlackoilWellModel_impl.hpp
index 60295a671f..3819323924 100644
--- a/opm/simulators/wells/BlackoilWellModel_impl.hpp
+++ b/opm/simulators/wells/BlackoilWellModel_impl.hpp
@@ -45,14 +45,14 @@
 #include <opm/simulators/wells/GuideRateHandler.hpp>
 #include <opm/simulators/wells/ParallelPAvgDynamicSourceData.hpp>
 #include <opm/simulators/wells/ParallelWBPCalculation.hpp>
-#include <opm/simulators/wells/rescoup/RescoupReceiveGroupTargets.hpp>
-#include <opm/simulators/wells/rescoup/RescoupTargetCalculator.hpp>
 #include <opm/simulators/wells/VFPProperties.hpp>
 #include <opm/simulators/wells/GroupStateHelper.hpp>
 
 #ifdef RESERVOIR_COUPLING_ENABLED
-#include <opm/simulators/wells/rescoup/RescoupSendSlaveGroupData.hpp>
+#include <opm/simulators/wells/rescoup/RescoupReceiveGroupTargets.hpp>
 #include <opm/simulators/wells/rescoup/RescoupReceiveSlaveGroupData.hpp>
+#include <opm/simulators/wells/rescoup/RescoupSendSlaveGroupData.hpp>
+#include <opm/simulators/wells/rescoup/RescoupTargetCalculator.hpp>
 #endif
 
 #include <opm/simulators/utils/DeferredLoggingErrorHelpers.hpp>
@@ -596,6 +596,34 @@ namespace Opm {
         RescoupSendSlaveGroupData<Scalar, IndexTraits> slave_group_data_sender{this->groupStateHelper()};
         slave_group_data_sender.sendSlaveGroupDataToMaster();
     }
+
+    template<typename TypeTag>
+    void
+    BlackoilWellModel<TypeTag>::
+    sendMasterGroupTargetsToSlaves()
+    {
+        // This function is called by the master process to send the group targets to the slaves.
+        RescoupTargetCalculator<Scalar, IndexTraits> target_calculator{
+            this->guide_rate_handler_,
+            this->groupStateHelper()
+        };
+        target_calculator.calculateMasterGroupTargetsAndSendToSlaves();
+    }
+
+    template<typename TypeTag>
+    void
+    BlackoilWellModel<TypeTag>::
+    receiveGroupTargetsFromMaster(int reportStepIdx)
+    {
+        RescoupReceiveGroupTargets<Scalar, IndexTraits> target_receiver{
+            this->guide_rate_handler_,
+            this->wellState(),
+            this->groupState(),
+            reportStepIdx
+        };
+        target_receiver.receiveGroupTargetsFromMaster();
+    }
+
 #endif // RESERVOIR_COUPLING_ENABLED
 
     template<typename TypeTag>
@@ -655,33 +683,6 @@ namespace Opm {
         }
     }
 
-    template<typename TypeTag>
-    void
-    BlackoilWellModel<TypeTag>::
-    sendMasterGroupTargetsToSlaves()
-    {
-        // This function is called by the master process to send the group targets to the slaves.
-        RescoupTargetCalculator<Scalar, IndexTraits> target_calculator{
-            this->guide_rate_handler_,
-            this->groupStateHelper()
-        };
-        target_calculator.calculateMasterGroupTargetsAndSendToSlaves();
-    }
-
-    template<typename TypeTag>
-    void
-    BlackoilWellModel<TypeTag>::
-    receiveGroupTargetsFromMaster(int reportStepIdx)
-    {
-        RescoupReceiveGroupTargets<Scalar, IndexTraits> target_receiver{
-            this->guide_rate_handler_,
-            this->wellState(),
-            this->groupState(),
-            reportStepIdx
-        };
-        target_receiver.receiveGroupTargetsFromMaster();
-    }
-
     // called at the end of a report step
     template<typename TypeTag>
     void
diff --git a/opm/simulators/wells/GroupStateHelper.cpp b/opm/simulators/wells/GroupStateHelper.cpp
index 5e7bbfee8a..da2527781e 100644
--- a/opm/simulators/wells/GroupStateHelper.cpp
+++ b/opm/simulators/wells/GroupStateHelper.cpp
@@ -1491,6 +1491,7 @@ GroupStateHelper<Scalar, IndexTraits>::worstOffendingWell(const Group& group,
 // Private methods
 // ---------------------------------------------------------------------
 
+#ifdef RESERVOIR_COUPLING_ENABLED
 template <typename Scalar, typename IndexTraits>
 ReservoirCoupling::Phase
 GroupStateHelper<Scalar, IndexTraits>::
@@ -1517,6 +1518,7 @@ activePhaseIdxToRescoupPhase_(int phase_pos) const
     throw std::logic_error("Invalid phase_pos in activePhaseIdxToRescoupPhase");
     return ReservoirCoupling::Phase::Oil; // just to avoid warning
 }
+#endif
 
 template <typename Scalar, typename IndexTraits>
 Scalar
@@ -1589,10 +1591,10 @@ GroupStateHelper<Scalar, IndexTraits>::getGuideRateVector_(const std::vector<Sca
 
 template <typename Scalar, typename IndexTraits>
 Scalar
-GroupStateHelper<Scalar, IndexTraits>::getReservoirCouplingMasterGroupRate_(const Group& group,
-                                                                            const int phase_pos,
-                                                                            const bool res_rates,
-                                                                            const bool is_injector) const
+GroupStateHelper<Scalar, IndexTraits>::getReservoirCouplingMasterGroupRate_([[maybe_unused]] const Group& group,
+                                                                            [[maybe_unused]] const int phase_pos,
+                                                                            [[maybe_unused]] const bool res_rates,
+                                                                            [[maybe_unused]] const bool is_injector) const
 {
 #ifdef RESERVOIR_COUPLING_ENABLED
     if (this->isReservoirCouplingMaster()) {
diff --git a/opm/simulators/wells/GroupStateHelper.hpp b/opm/simulators/wells/GroupStateHelper.hpp
index 917cab4437..b46fe54547 100644
--- a/opm/simulators/wells/GroupStateHelper.hpp
+++ b/opm/simulators/wells/GroupStateHelper.hpp
@@ -346,12 +346,14 @@ public:
                        DeferredLogger& deferred_logger) const;
 
 private:
+#ifdef RESERVOIR_COUPLING_ENABLED
     /// @brief Convert active phase index to ReservoirCoupling::Phase enum
     /// @param phase_pos Active phase index (0, 1, or 2 in a 3-phase model)
     /// @return The corresponding ReservoirCoupling::Phase enum value
     /// @note This uses the canonical phase ordering (Oil=0, Gas=1, Water=2)
-
     ReservoirCoupling::Phase activePhaseIdxToRescoupPhase_(int phase_pos) const;
+#endif
+
     //! \brief Compute partial efficiency factor for addback calculation.
     //!
     //! The addback in constraint checking must use the partial efficiency factor