Assembly with a linked file

Good day,
Trying to figure out a way to do this.

I am working on a craft and would like to have two versions of it. One will be a flat file - all objects flat to the ground - and the other will be an assembly file to make sure fit and finish are accurate and precise.
The flat version will be used for CNC purposes using BlenderCam.

I have in mind a script that will break the assembly down to the flat version but I’d like to keep them both.

I thought this could be done with a shift-d component…need to revisit that idea.

My question: how can I link a file that has parts in different orientations, re-orient and edit, and have that show up back in a master file? I want the master file to be the assembled one. Perhaps the master needs to be the flat one?
I think I just need to see others ideas to get this concept doable in my head.