I just downloaded a nice space shuttle connected to its boosters. figured I wanted to improve it. its impossible to disconnect parts and reconnect them in the correct place. only the parts connected to the control module as considered "root" and editable. the rest is a solid block.
Ideally I would group pieces together, connect and disconnect them as a single piece. Importing groups from other projects would allow me to connect a shuttle to the top of a plane.
we need to scaling option for entire grouped parts too.
I think you can do what you want using the existing group/ungroup combined with the existing subassembly saving and loading. Not sure I'm reading this right