Carp - Multiple instances synchronization


I have 2 firewalls: F1 and F2. Each of them have 3 interfaces: eth0, eth1 and eth2.

My problem is that, when I use carp, I can add on each couple of interface a virtual IP. But some times, a firewall can have some of its interfaces on BACKUP mode and some other on MASTER mode.

For example, F1 is some time with eth0 and eth1 on MASTER, and eth2 on BACKUP...
And in this case F2 is with eth0 and eth1 on BACKUP and eth2 on MASTER.

Is it possible to synchronize all interfaces mode on each firewall on BACKUP ou on MASTER?

The sysctl net.inet.carp.preempt should be set to 1 for this to happen. Someone else was reporting that it might not be working as it should, but I haven't had time to test.