Howto Filter Mails

[Meshbah Uddin Ahmed]

hi,

i have used Postfix + MailScanner + ClamAV in FreeBSD. All r
sucessfully working. but i face a prb, i want to filter mails through
subject or body but i cant. whereas i can check mail by header.

because i get some mails, which domain i dont want to block, i need to
block those by searching a string from body or subject.

so, can u pls suggest me, how can i do that. or any idea.

thanks
meshbah