ACD Queue OverFlow

I have been looking through the Asterisk Docs looking for a feature we currently use on our Cintech ACD.

The feature is queue overflow. This means, we have some agents logged into queues a, b, and c. We have another queue (d for example). When either a, b, or c have more than x number of calls, or a call has been queued for more than x number of minutes, the call overflows into queue d.

Since our call volume fluctuates, we try to allow some people to get other tasks completed without being distracted with phone calls constantly, yet they will get calls if our staff gets busy, and customers are waiting.

Does Asterisk (or any add on) support this feature? Also, whats the best managment tool for call centers with a high incoming call volume. We really don’t have a large volume of outgoing calls.