|Just change the Default Gateway to the edge router you want them to go through. The only problem is that you will have to use static IPs this way.|
You could setup two DHCP servers for each gateway. Not sure if you are using a /24 network but set the first DHCP server to 3-126 and the second to 127-254 and setup the gateway for each.
This is also assuming that your edge routers are on .1 and .2.