Message Forwarding

[Database Administrator]

We are currently running Lotus Domino Server version #.#. We will be
migrating to Microsoft Exchange in the near future. Both are up and
running on separate domains for testing purposes. Lotus is running on
abc.com and Exchange is running on abc.biz. We would like to set up a
rule to forward all email that comes in to abc.com that it forwards to
abc.biz. The difficult part is, we want to configure the system so
that when we reply to an email from the abc.biz that it routes back
through the Lotus server so that it appears to the recipient to come
from abc.com, not abc.biz. Our abc.biz domain is not public and is for
testing purposes only so we want all email to appear to come from
abc.com even if it is truly being sent from Exchange on the abc.biz
domain.

Just to be sure I'm clear, here is an example:

message sent to user@abc.com (Lotus) is forwarded to user@abc.biz
(Exchange). User@abc.biz replies to email. Message is routed through
abc.com domain so that recipient sees email is replied to from
user@abc.com, not abc.biz

Is this even possible to do and if so, any advice would be greatly
appreciated.

Regards,

Eric