An Out Of The Ordinary Hotlinking Question - Stopping Hotlinking From OTHER websites?

[rokked]

I've been scouring the net for this, and thus far have found nothing.

We're having a problem at our forums with members continually hotlinking to our forums from other websites. This is the opposite problem most people are worried about, but it's gotten us into legal trouble in the past, and though most of our members abide by the rules, some of them are still hotlinking from sites rather than uploading at an image host.

Is there any kind of hack, or plugin, or even code that can disable hotlinking FROM other websites? Obviously you can ban it altogether, but what we're looking for is a way to disable it from CERTAIN sites. For example, hotlinking from photobucket, imageshack, etc. (hosts that are meant for hotlinking) would be permissable, but hotlinking from non-approved sites would automatically fail. Is this possible in VB, or are we just going to have to turn up the hotlinking watch to 24/7?

I appreciate anyone who can help. Our site owner is threatening to shut us down if we can't fix this problem.