I would double the number of Archicad stories (one additional for each unit floor) so that each floor level has it's own AC storey. Combine in layouts as necessary for output.
This should allow you to use multistory walls and cut / projected display. If that isn't feasible you might want to avoid multistory walls and use only symbolic display, but I think that is more work.
AC4.1-AC26SWE; MacOS13.5.1; MP5,1+MBP16,1