[exim] Save all email for a domain

Hello,

Could anyone tell me if its possible (and if so how) to save a copy of every incoming and outgoing mail message to another account on the system? For legal reasons we have to save a copy of everything, even something that a user sent and then deleted himself.

We currently accomplish this using the journal feature of Exchange, is there some way to do it with Exim?

TIA!
-Chris