Block posting of specific URLs

[Streetjob]

Thanks but then the post will still go through. And there will either be nothing there to replace the url (if you did not put in a replace) or there will be the replace information e.g. ****. This is tacky in my opinion and would also affect all prior posts..

I now have rules in place that specific urls are not to be posted. I want to have users abide by these rules and prevent them from posting these urls in the first place.

Please help!

Thanks!