Using DCC To Filter Message Bodies

Hello,

  I'd like to use DCC to filter spam messages based on the contents of the body.
 IE, I add the message about Britney Spears's naked playtime (which I get about
6 times a day, from various servers and addresses) to my database and then when
that message body comes in, it is blocked or an X-This-Is-Spam header is added.
 Anyone have a howto on how to set this up?  I already have DCCm up and going
via sendmail 8.12.2's milter, and I can report messages via dccproc, but I don't
get the part about filtering based on message body's checksum being in the
database.  All I'm getting is a count of how many times a particular message has
arrived, whether it's been specifically reported or not.

  I guess waht I'm asking is how do I ONLY match messages that I've specifically
set to be matched by manually reporting them with dccproc (or any other manual
reporting tool).