ACL Policy Daemon for Postfix <http://www.apolicy.org/cgi-bin/moin.cgi>might do the trick without me having to write the policy daemon myself. It provides numerous ACL methods<http://www.apolicy.org/cgi-bin/moin.cgi/Tutorial>and Regex ACLs <http://www.apolicy.org/cgi-bin/moin.cgi/AclList>.
Ville
