[CentOS] Postfix question: How to reject email with a certain subject header

Hello everyone,

Occasionally I get emails which have a subject header of "Rejected posting 
to Blah", from a listserv I am on. Without going into a 10 page diatribe 
of why, I'd like to reject these automatically, sending them to /dev/null. 
I used to run Sendmail and that was pretty easy to do. How can I do this 
under Postfix under CentOS 5.3?

Any help is appreciated. Thanks!

Gilbert

*******************************************************************************
Gilbert Sebenste                                                     ********
(My opinions only!)                                                  ******
*******************************************************************************