NRPC Routing Based on Directory Assistance

Hello,

This problem is not so “complicate” but I couldn’t find the best solution, please help me I really need URGENT an answer.

I have two domains A and B.

In domain A I have a HUB server which receives internet e-mails.

In domain B I have 3 servers XB, YB and one HUB server HB.

Right now I send notes mails from domain A to B through HUB server HB.

In the future I want to send the notes emails from domain A directly to server XB (not through HUB server HB) and even more to continue to be able to send email from domain A to server YB (the second one) through HUB server HB.

How is this works? Can work based on Directory Assistance and Domain Connection?

Do you have a better solution?

Thank you very much for your help and please reply to me.

Regards,