Word censor usergroup setting? Or ideas?

[indie]

I have members in a certain usergoup that are allowed to post links to video clips, and in a certain forum.

The problem is, regular members post the links in other areas of the forum.

I was thinking of ways to prevent members on my forum from posting links to video clips, unless they are in a certain usergroup. The way I thought of was, to censor the file extensions for regular users. There are only a few popular ones, like .mov, .wmp, .avi, etc. So by censoring, it would make the link not work.

How would I go about censoring those by usergroup, or do you have any other ideas about limiting the links to usergoups or certain forums?

Thanks