sender and recipient dependend routing in a single postfix engine

[Ilja Beeskow]

Hello @all

I wonder if there is a possibility to tell postfix how to route e-mails sender 
and recipient dependent. Our scenario is as follows.

Postfix is anti spam and anti virus gateway for a couple of domains. Incoming 
mail for all these domains is forwarded by the Provider to this gateway and 
distributed to several internal mail servers (exchange, domino) in respect to 
the transport table.

For sending e-mail all internal mail servers use the gateway as a smart host. 
Sending mail to each other works as well as sending mail to external 
recipients. Additionally there is a special requirement to send e-mail for a 
given list of domains through another gateway and not the provider's. This is 
done by using a second transport table.

Now the question:
Is it possible to have an additional mechanism to alter the second routing 
decision in respect to the senders address?


kind regards

Ilja