certain addresses through certain network cards
 

I have a client that needs to access certain websites through one nic and other sites through another nic. Is there a way to edit the hosts file so certain addresses will go through a particular card?

Normally, that is done with route:
route displays the routing table
route add -host 10.9.8.7 eth0
route add -host 7.8.9.10 eth1
See man route for details.