I want to reject emails to my postfix server based on more than one criteria, specifically I want to block emails from Russian email addresses (or that contain Cyrillic characters, but this I suspect is harder) that are addressed to two specific recipients (but not if addressed to others).

I feel this should be straightforward especially since the 'mail from' and 'rcpt to' addresses are both supplied right at the start of the smtp negotiation. But I can't find a way to do this with postfix, and am not sure if I need some add-on package (milter?).