Confernece Room Schedulling on Exchange

Ahhh..
Back to the good old conference room scheduling dilemma. Here is what I am doing, but it just isn’t enough, please help.

I have created users and mailboxes for conference rooms and logged on as these user/conference rooms and set the calendar to act as a resource. Which accepts and process meeting requests and cancellations. I have also set decline conflicting requests.

All is well, if you attempt to schedule the conference room as a resource. If you don’t, if you try to schedule the room as “required” or “optional”. You are now able to over book the room.

Your thoughts/solutions?