Is there a way to group walls/elements that occur on different stories?
- select them in the 3D window and 'Group'.
The above answer of Ben Frost is 100% OK, but Link's advice may be of special interest for ARCHICAD users:
And if you want to include 2D elements, you will need to group those with at least one 3D element in the floor plan(s) before going to the 3D window and grouping them again.
The good thing is that it if you edit a multistory group in plan it will show all the elements over all stories as selected.
The original thread can be found in our Design Forum.