The problem is, my office has multiple computers, and there is only one account (admin) on every machine, all with the same password. So if I bring a personal firewire drive and attach it to my machine, everyone on the network can access it. What I need is a way to STOP file sharing for this external drive without adjusting permissions, because there is only one set of permissions for this computer, and everyone on the network has access to that account.
The only way a drive would have it's sharing enabled is through the Sharing menu in system preferences. Access the File Sharing menu inside there and remove your drive from the list.
That's the only thing I can come up with besides changing the drive permissions.
Hope it helps :)