Forum Moderators: phranque
Welcome to WW
If you know the URL's of the sites that are referring traffic, you could setup a redirect by referrer rule (or condition) in .htaccess, unfortunately this will not deal with typed in requests (or copy/paste) or those originating from a mail client.
I think this request would probably be best of being made in the Apache Web Server [webmasterworld.com] forum. That is also where you will find a lot of relevant posts on this subject.