For this you need to create two VLAN or sub-interfaces on the router and start routing there. You need to add two static routes saying that for each network (VLAN), outgoing interface is IP for the Internet. VLANs will not talk to each other until you add any route for the same. I don't know whether your router will support creating VLAN interfaces or sub-interfaces. You might need to invest a little more in the router.
For more information, learn what options you have forsecuring the Internet-connected branch office.
This was first published in May 2005