defer mail for unknown recipients for one domain only

[Sebastian Wiesinger]

Hello,

I have a setup with handles a few virtual domains. For one domain only
I want mails not to be rejected with an 5xx error code but be deferred
with a 4xx error code. Is that possible?

Regards

Sebastian

-- 
GPG Key: 0x93A0B9CE (F4F6 B1A3 866B 26E9 450A  9D82 58A2 D94A 93A0 B9CE)
'Are you Death?' ... IT'S THE SCYTHE, ISN'T IT? PEOPLE ALWAYS NOTICE THE SCYTHE.
            -- Terry Pratchett, The Fifth Elephant