[lxc-users] LXC container isolation with iptables?

[bkw - lxc-user]

I have an LXC host.  On that host, there are several unprivileged 
containers.  All containers and the host are on the same subnet, shared 
via bridge interface br0.

If container A (IP address 192.168.1.4) is listening on port 80, can I 
put an iptables rule in place on the LXC host machine, that would 
prevent container B (IP address 192.168.1.5) from having access to 
container A on port 80?

I've tried this set of rules on the LXC host, but they don't work:

iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
iptables -A FORWARD -j DROP -s 192.168.1.5 -d 192.168.1.4

Container B still has access to container A's port 80.

Thanks, in advance, for any assistance you can provide.