I installed freifunk 1.4.5 on wrt54gl (5 in number). All the routers are pinging each other wirelessly. now i want to setup the routers as,

------ wireless connection
______ wired connection

Now i will accomplish VoIP communication between machine 1 and 2. but with multihop characteristics of the network. as the routers are in the same room, they are in range of each other, so router1 directly connects to router5 which i dont want. I want that the communication is carried out through multi hops i.e router1 can only connect with router2 or 3. similarly, router 2 may only connect with router 1 and router4. and so on. can any body plzz help me how to do this please... i can also access the router's shell. i hav also heard that this can be done through iptables or ipfw, but i dont know how to use them. also whether they r there in freifunk 1.4.5 or not..... please help me out....