[exim] Problem Of Duplicate Mails In Exim

Hi to all,

i am facing a problem of duplicate mails. In antivirus.exim i have set
incoming & outgoing mails of some users (say ABC & DEF) copied to another
user (say XYZ).
Earlier, it was working fine means all the incoming mails and outgoing mails
of user ABC & DEF also forwarded to xyz. After some time i have made the
same forwarding also tp user PQR. Means now apart from user XYZ, PQR is also
getting all the incoming & outgoing mails of user ABC & DEF. But since then
i am facing problem of DUPLICATE Mails To PQR.

PQR is getting 2-3 duplicate mails of all the incoming & outgoing mails of
user ABC & DEF.

what should i do in this case?
Please suggest something on this with proper syntax, as i am NEW to EXIM.

ThankU

KeenLearner