[Lee Wilde]

I'm not sure I understand what you mean, so please forgive me if this sounds like I'm trying to tell you how to suck eggs.....(you may have figured out the solution by now anyway)

Have you thought about creating a number of usergroups, e.g. Zone 1 members, Zone 2 members...etc. And then separate your existing members into these usergroups and then in forum permissions only give access to the forums in Zone 1 to Zone 1 members....only give access to forums in Zone 2 to Zone 2 members.....and so on.

So when anyone clicks on "forums" in the navbar...they will only see the forums they have permission to see.