Question : source based routing?

I have a router with multiple interfaces. I want to route to my next hop based on the source address. You can think of this as being a router at a small ISP with multiple Internet connections, but I only want to route certain customers over one of the connections.

interface BVI10
 desc Internet connection
 ip address 12.3.10.1 255.255.255.252
!
interface BVI11
desc - corporate network, devices on BVI12 and BVI13 should not route via here
 ip address 1.1.2.1 255.255.255.252
!
interface BVI12
desc customer 1
 ip address 2.3.10.1 255.255.255.240
!
interface BVI13
desc customer 2
 ip address 2.3.11.1 255.255.255.240
!
interface BVI14
desc internal LAN
 ip address 8.3.11.1 255.255.255.0


The corporate network uses public IP addresses, and of course I have my normal default route to get everything else to the Internet. I currently have a statement that just says
ip route 88.88.0.0 255.255.0.0 1.1.2.2
ip route 0.0.0.0 0.0.0.0 12.3.10.2
So all my traffic destined for corp-net goes over the BVI11 connection. How do I get my traffic from BVI12 and BVI13 to go over the normal internet connection, reguardless of destination, while traffic from BVI14 DOES go over the corp-net connection.

I thought a policy map would work here, but that would route all my outgoing traffic across a given connection, when I only want to route for a specific destination.

Answer : source based routing?

Policy route-map is your solution.
You define the source/destination pair with an access-list, then tell the router what to do with it

access-list 101 permit ip 2.3.11.0 0.0.0.255 any
access-list 101 permit ip 2.3.10.0 0.0.0.255 any

access-list 102 permit ip 8.3.11.0 0.0.0.255 any
 route-map POLICY1 permit 10
   match ip address 101
   set ip  next-hop 12.3.10.2

 route-map POLICY2 permit 10
  match ip address 102
  set ip next-hop 1.1.2.2

Interface BVI11
   ip policy route-map POLICY1
Interface BVI12
   ip policy route-map POLICY1
Interface BVI14
   ip policy route-map POLICY2