Multiple copies - mail problem

[NV]

Dear All

We have a pop account abc at xyz.com, under which we have test1 at xyz.com 
....test5 at xyz.com. The problem we are facing is when we fetch mails that 
are copied to multiple addresses, we get that many copies in each mail 
boxes locally.

e. g. To:test1,Test,3,test5
test1,3 and 5 all will receive threee copies each of the message. (total 
9 copies)

When we check the mailbox on the pop server, there are three copies of 
the message, with the same message ID.

How can we eliminate duplicates being delivered the the local mail boxes.

The details of our system is

sendmail 8.12.x
fetchmail 6.2.5
RHEL ES 3.0

Thanking you.

Regards

Nilesh