You can have two different NICs in a server and they can be used to route to different network segments. However, only one can have a default Gateway.
For example, I have one like this in my network. One NIC points to my local segment and has a normal IP, Subnet mask, and Gateway. The other one is attached to a partner network. It has an IP and Mask, but no GW. I have a routing table on the server that says if an application that runs on this server tries to access an IP on the partner network, use the second NIC. So the 0.0.0.0 route is my local NIC and other routes built into the routing table point to the second NIC.
