Maildrop filtering for virtual users (postfix)?

[Thomas T. Veldhouse]

FreeBSD Questions -

Has anybody implemented filtering for virtual users via Maildrop?  I
have a postfix installation with a mysql backend running virtual users
for several virtual domains.  I would like to implement filtering
(manual configuration of files is fine).  Does anybody have any
experience getting this to work well?  FWIW, I am using postfixadmin to
manage everything.

Thanks in advance,

Tom Veldhouse