Easy, create a new forum, and on the permissions tab only allow admin's and moderators, then go in and edit each moderators account and allow them access to the new forum.
why would you have to edit EACH moderator? seems to me, that on my board i just let 'moderators' have access and they get axx by being a moderator..
i'm assuming that you aren't giving each moderator the ability to actually moderate that forum... hehe