Can I set all Outlook/Exchange Resource Calendar items to busy?

I am new to Exchange/Outlook (2007) and am setting up Resources for use with Outlook. I’ve noticed that if someone books out a resource and marks their time as ‘Free’, the resource is also marked as ‘free’. It will be common for someone to book out, say, a camera and still be free for other meetings whilst the camera’s free/busy must obviously be set to busy to avoid double bookings. Is there a way, as an Exchange administrator or owner of the Camera mailbox to simply override all calendar items to be busy?