Don't know if you can do that but what you can do is if you post a WANTED for a certain type of boat then make the comment that the reply person send you a PM which can be done by clicking on your user name which will appear with the request.
Just be sure your e mail address has been filled in. Then you will get an e mail from T.F. advising you without the replying person contacting you directly. Then you two can exchange e mail addresses.