While this isn't an answer to your problem, it may help you in the long run:
I've worked in offices that laid all of the floors over each other in model space.
What I did in that office is a second best solution, but they were really resistant to the idea of xrefs.
I changed the layer naming convention to be by floor, so instead of an A- orginator code the layers were by floor 1- 2- 3- etc.
I then built a toolbar with macros that turned off all layers and re-turned on 1-*. The next button the same for 2-* etc...
It was a good work around that kept everyone reasonably happy.
The best solution, however, is learn the aggregate xref method. It works a lot like the old mylar pinbar system, but doesn't suck, and won't rip gashes in the soft underbelly of your forearms, and clothes.
You basically break the drawing up into sets of layers each in a separate dwg file. The you xref those together.
It's awesome for layer control and sorting, and re-using information.
Ever show an elevation beyond in a section drawing. Don't copy it and let it fall out of date, xref and xclip it into your section. Then when you change the elevation, the background of your section will update too.
