routing problem

[noname]

Hello! I'm trying to solve a problem...
I have two ethernet devices, ngeth0 and ngeth1, which are in the same
network and both have the same gateway. I need to direct packets
coming from definite ips through ngeth0 and from other adresses
through ngeth1. If there was two different networks/gateways it could
be done with ipfw, but now I need two routing tables, one with default
route going through ngeth0 and enother with default route going
through ngeth1. There is iproute2 for linux which does the thing. But
how can it be done in FreeBSD 5.4? Can the Bird help? I've tried to
read user's guide for the Bird, but it is quite hard to understand it.
There should be some practical examples. Can somebody give some hints
on this subject?

Best regards, Nikolai Koudelia