sendmail with two domains having prob in mail receiving

[lasa]

Dear Sir,
Sendmail is configured to receive mail from two domains
xyz.com<http://xyz.com>and
xyz1.com <http://xyz1.com> fine .For this configuration of adding line to
"Cw xyz.com <http://xyz.com> xyz1.com <http://xyz1.com>" to
sendmail.cf<http://sendmail.cf>file and configuring DNS for two
domains with two static IPs done by me. But
if a mail send by out sider to abc at xyz.com account it is being rceived by
user account abc at xyz.com as well as user account abc at xyz1.com. I only need
to receive the mail to the relevent mail account abc at xyz.com and stop
copying the same mail to other account abc at xyz1.com. How can I do this in
linux?
--
Lasantha Amarasinghe
Sri Lanka