diff --git a/Pmodules/libpbuild.bash b/Pmodules/libpbuild.bash
index 6ff5762..6a98169 100644
--- a/Pmodules/libpbuild.bash
+++ b/Pmodules/libpbuild.bash
@@ -746,21 +746,38 @@ pbuild::make_all() {
 		}
 
 		[[ -n ${GROUP} ]] || std::die 1 \
-					      "${module_name}/${module_version}:" \
+					      "%s: %s" \
+					      "${module_name}/${module_version}" \
 					      "group not set."
 
-		# define defaults if not set in configuration file
-		: ${Compiler_HIERARCHY:='${COMPILER}/${COMPILER_VERSION}'}
-		: ${CUDA_HIERARCHY:='${COMPILER}/${COMPILER_VERSION} cuda/${CUDA_VERSION}'}
-		: ${MPI_HIERARCHY:='${COMPILER}/${COMPILER_VERSION} ${MPI}/${MPI_VERSION}'}
-		: ${HDF5_HIERARCHY:='${COMPILER}/${COMPILER_VERSION} ${MPI}/${MPI_VERSION} hdf5/${HDF5_VERSION}'}
-		: ${HDF5_serial_HIERARCHY:='${COMPILER}/${COMPILER_VERSION} hdf5_serial/${HDF5_SERIAL_VERSION}'}
+		# define hierarchies
+		if [[ -v COMPILER_VERSION ]]; then
+			Compiler_HIERARCHY='${COMPILER}/${COMPILER_VERSION}'
+		fi
+		if [[ -v COMPILER_VERSION ]] && [[ -v HDF5_SERIAL_VERSION ]]; then
+			HDF5_serial_HIERARCHY='${COMPILER}/${COMPILER_VERSION}'
+			HDF5_serial_HIERARCHY+=' hdf5_serial/${HDF5_SERIAL_VERSION}'
+		fi
+		if [[ -v COMPILER_VERSION ]] && [[ -v MPI_VERSION ]]; then
+			MPI_HIERARCHY='${COMPILER}/${COMPILER_VERSION}'
+			MPI_HIERARCHY+=' ${MPI}/${MPI_VERSION}'
+		fi
+		if [[ -v COMPILER_VERSION ]] && [[ -v MPI_VERSION ]] && [[ HDF5_VERSION ]]; then
+			HDF5_HIERARCHY='${COMPILER}/${COMPILER_VERSION}'
+			HDF5_HIERARCHY+=' ${MPI}/${MPI_VERSION}'
+			HDF5_HIERARCHY+=' hdf5/${HDF5_VERSION}'
+		fi
 
 		# evaluate
 		local names=()
 		local vname="${GROUP}_HIERARCHY"
 		if [[ -n ${!vname} ]]; then
 			names=( $(eval echo ${!vname}) )
+		else
+			std::die 1 \
+				 "%s: %s" \
+				 "${module_name}/${module_version}" \
+				 "not all hierarchical dependencies loaded!"
 		fi
 
 		modulefile_dir=$(join_by '/' \