Copy/Pasting in separate models

We are working unit plans in a master unit file. These units are then copied/pasted into their own individual ‘shell’ model, which is then linked into the main apartment project model. This allows us to link in units (not using groups), but documenting and editing the units in a separate file—independent of the main project.

Is there a method of automating the copy/pasting process? I’m not able to find a good method as it technically involves multiple models (the master unit file and the individual ‘shell’ models).

I’ve contemplated using a ‘saveas’ loop, which would erase everything but 1 unit at a time, then save the project w/ a unique file name…but I can’t find a way to ‘undo’ something in Revit to get all of the units back as the script works it way through the list.