Join weldment bodies from different assemblies

From a recent project we discovered a limitation in the workflow when working with big weldment assemblies.

The design is made from different assemblies that has a weldment part in them.

It would be very useful if SolidWorks could join or gather different bodies from different assemblies in one command.

Se this example where this design needs to be documented. It is parts med from different assemblies.

The result should be like this

Solidworks