[exim] drop, deny, blackhole, discard acl use

Hi All,

I'm trying to accept but discard messages sent to a particular user,
even though most of the messages are coming from inside (trusted
server) from server A to server B, i have access to exim B but not
evil but trusted A. Thus everything i try fails, and the messages are
just forward as normal. I've had success with mails that come from
untrusted outside though.

For instance, in an internal bounce situation where i don't have
access to the other mail server.

Cheers,
Kristian