Im trying to set the relayhost of a postfix server based on the user sending an email.

I think that you can set witch smtp server to relay a message based on a destination using the transport_maps option (where destination domain is message will be sent through but i want to be able to select the relayhost based on the sender.

For example: user(at) sends message to user(at)
because the sender's domain is use

Is what im trying to do possible?
Is there something similar to what im trying to do?