IPtables on DD-WRT - Bridge communication

I have a Broadcom based Linksys WRT160n router running DD-WRT build 14896. The LAN and wireless clients get a 192.168.1.xxx IP address. They are on br0. I have a guest network in the 192.168.2.xxx range running on br1. The guest network has internet access. I have no firewall/iptables rules declared.

Here's what I want to do: allow communication initiated from br0 to flow to br1. Disallow communication initiated from br1 to br0 (which seems to already be happening).

Right now, I can't ping or tracert from a 192.168.1.xxx host to 192.168.2.xxx host. I would like to be able to make that happen.

Is this something that can be done?