[exim] Get spamassassin to deliver spam to a special mailbox…

I am Is there a way through a special router to get exim to deliver spam
to a special local email address for logging and verification?

ex:  I want all messages marked SPAM deliever to spam@???, but
also delivered to the user.. This way I can have a log of messages
marked spam, and tighten up my spam controls..
    I am running exim 4.5 with spamassassin called via a router, not
exiscan...

Thanks...

Joe