redirecting emails arriving from a particular ip or ip's.

[jerry....@gmail.com]

Hi sendmail gurus:

I want to relay mails that originate from a particular ip or domain.
The email will arrive at sendmail server "A" from the IP and I then want
to redirect that email to smtp server "B". From B the email will be sent on
to the to: location, wherever that may be.

Other mails are coming into sendmail server "A" from other locations but I
don't want to redirect those emails.

How can/should I implement the above.
I am using sendmail 8.13.8 on a centos 5.7 box.

Thank you very much.

Jerry