[Mimedefang] common practice

[Cor Bosman]

Hi all, we're setting up a MD system and im wondering what the best practice
is for dealing with email sent to multiple recipients that you'd like to
block after the sendmail DATA phase (for instance after SA has said it's
spam). Obviously you cant individually send 5xx after data phase. Only can
either silently drop the message or bounce.  Both have their bad points.

What do others do?

Cor