sendmail domain problem

hello eveyone .

i am having a problem concernig sendmail and inbox. On the server that
i run sendmail the
dns record (in another pc is the DNS) matches to the same ip address
for both domain names.
The problem is that a unix user(not a virtual one) when a mail arrives
and he/she uses pop he gets the mail twice for the two domains ?
I think this can be solved from an mda but i am not sure.
By the way i prefer postfix as my mta and maildrop as my mda but i have
to deal with sendmail
and other services that i don't like.
anyway if anyone can give me a hint i would appreciate it



verestio