Seperating 2 mail domain for outgoing mails by an IP address

Hello forum,

I am looking for a solution that will enable me to send email with
different IP addreess based on the sender domain.

Lets take the following scenario: i ahve a an exchange server that
contains 2 mail domain and what i would like to do is that mails from
doman A.com will be delivered with ip addresss 1.1.1.2 and emails from
domain B.com will be delivered with ip addresss 1.1.1.3.

Thre problem today that i got a load balancer with 3 exits each one
with a different IP address, so on the recipent side the emails is
blocked due to Reverse DNS or NSlookup failure.

I have read several threads but still the issue is not clear.

In the buttom line i would like to re-write the sender's emails header
to pass the tests above.

Is it possiable in postfix or sendmail? or any other solution.

Kindly regards,

Yossi Mor