Queue failover on all agents busy?

Basically we have a two-tier system that is working fine failing over on timeouts. What I am wondering is if there is a way to get the first queue to forward the call to the secondary failover queue if all agents in the first queue are busy. This would eliminate the caller having to wait for no reason.

AsteriskNOW 1.7 with FreeBPX 2.8.0.3.

Thanks!