My experience in houses in Germany indicates no such range problems. I have no bluetooth access outside of each room. It really works only within each specific room.
Is the current orbiter for the Nokias not capable of the automatic follow-up, or should just not be used?
the Nokia orbiter is the native linux one compiled for arm. It uses an IP (WLAN) connection and not the "BD" code for orbiters (bluetooth "bridge" to dcerouter).
I don't know if there is a DCE message to change the room on an orbiter. If yes, it should be easy to use some bluetooth scanning software on the N800 (maybe a "hcitool scan") and hack a small script to send messages based on the findings.. If the HWAddr for BT-sticks is stored in the database you should be able to look the room information up from the MAC, too.
but i'm only guessing and don't know for sure. What i know for sure is that there is a better approach to this problem than this quick and dirty hack