How to segregate smtp traffic to different Server based on our Sender domain not Recepient Internet domain

Dear All,We have a different domino domain and mails coming from all these domain is routed through our Hub server then hub server will delivered that mail to our first ironport to the internet.

Our requirement is mails coming from our specific domain (e.g.- xyz.com) after coming to our Hub server routed through secondary ironport to the internet.

Any body have an idea how to do this?

Thank u very much in advance.