Networking :: Iproute2 Load Balancing Without Default Route?

I'm trying to set up load balancing using iproute2 following this guide. I've got 4 dsl links as follows:

eth1 - 100.100.100.1
eth2 - 100.100.100.2
eth3 - 100.100.100.3
eth0 - 111.111.111.111 (main uncapped line)

eth0 is the default route, and eth3 is being used for something else. So what I want to do is load balance browsing between eth1 and eth2. I've added all of the routes in the LARTC guide, but the command to enable the load balancing:

Quote:

ip route add default scope global nexthop via $P1 dev $IF1 weight 1 nexthop via $P2 dev $IF2 weight 1 obviously involves creating a new default route. Since I'll be using Squid to push the traffic through the relevant line, how can I set up a load-balanced link for eth1 and eth2 without changing the existing default route on the server?