How to fake Per-Recipient Data Responses (PRDR)?

[MRob]

Hello, short of Per-Recipient Data Responses (PRDR) becoming standard, 
may I ask how administrators are faking it? I understand you can 
temp-fail all but the first rcpt-to, but how to do this in Postfix? Does 
it require a custom milter? Surely there must be a published solution 
somewhere?