Are you dead set on doing this upside down? It might be easier to turn your second level menu into the first level and the rooms into the second level. It might make more sense to the users too. Then rooms can just be permissioned and the menu will work very easily with no mucking around.

Nancy

Injustice anywhere is a threat to justice everywhere. -- Dr. Martin L. King, Jr.

From:
              Rob Thorne

            I'm looking into a two tiered menu in a D7 application where
            the second

            level of the menu is standard, but the top level is
            different for every

            user.

            To make this concrete, suppose the user is a teacher at a
            school where

            the teacher uses multiple rooms, and needs to order
            materials for each

            room separately.  Each teacher has a separate list of rooms,
            but the the

            pages we track -- class lists, crafts inventory,
            furniture... are the

            same for each room.