[exim] Mail archive duplicates

Hi,

as I already wrote in another thread yesterday, I'm setting up an e-mail
archive for some users. Now I got it working, but I'm getting duplicates
into the archive.

I have set up the following router to catch outgoing mail:

archive:
debug_print = "R: archive for $authenticated_id"
driver = manualroute
condition = ${lookup {$authenticated_id}
partial-lsearch{CONFDIR/archive} {true}{false}}
route_data = ${lookup {$authenticated_id}
partial-lsearch{CONFDIR/archive} {$value}}
headers_add = X-Archive: $authenticated_id
transport = remote_smtp
unseen

In addition to the normal delivery, this delivers mail from
authenticated users to a machine as declared in CONFDIR/archive.

Now, a user that is in CONFDIR/archive may send mail to some local
address, let's say info@domain. Let's say that info@domain is forwarded
to name1@domain and name2@domain which are routed to user1@host and
user2@host. In this situation, I get 5 mails into my archive, one for
each routing stage. (The log mentions all these interim addresses with
their own delivery line.)

How can I avoid that? Checking for dups on the remote site isn't an
option, I think.

Thanks,
Peter