У postfix в *_restrictions можно использовать regexp, например:
В main.cf:
...
smtpd_sender_restrictions = permit_sasl_authenticated, permit_mynetworks, check_sender_access regexp:/etc/postfix/sender_access, reject_non_fqdn_sender, reject_unknown_sender_domain, permit
...
В /etc/postfix/sender_access:
/.*@friends\.ru/i OK
/.*evil\.org/i REJECT