[Exim] Exim 4.34 and 2003 Active Directory LDAP queries

    I have Exim 4.34 running in front of an Exchange 2003 server, and
have a question regarding proper implementation of LDAP queries via Exim.
    I would like to be able to use Exim to LDAP query active directory
and from the results determine what the actual e-mail address is of a
user object, and then either directly deliver the e-mail to the address,
as in the case of VPO addresses ie: mail arrives to our Exim server that
is to user1@??? but is actually destined for
user1@???, or to deliver the mail directly to our exchange
server, as in the case of mail that is destined for our one local mail
domain; sc.younglife.org ie: user1@???
    I'm not having any trouble getting the LDAP query on it own to
function and return the desired results, but I'm still pretty uncertain
of how exactly to get Exim to correctly interpret the query results and
act on them accordingly.  Has anyone been able to implement something
similar?  Could this functionality be done by a single router?
Thanks much, and I'm sorry if this doesn't make much sense.
Tim Sexton