Red,
you can do it by checking global variables in your 2Dscript (go to AC help-GDL manual-Appendix-Global variables-Story Information) so you can hide the object on particular storeys. However, it does not work really good, because when you hide the object it will leave a hotspot on plan (and particular storey) instead (basically, you can not hide it completely) and what is worse you can accidentally select and delete it. So it is a very dangerous solution. Unfortunately, this feature has been on the wishlist for ages.
::rk