Priority Queues/Weighted queues

Hi, I would like the feature of a priority queue where you can have one or two people signed in and receive all calls. Then have another queue that ONLY receives calls if the first queue people are on a call. Even nicer if we could say wait 20 sec then flow into the 2nd queue. 

What is now happening we have to watch to see when calls are waiting and then pick up the call without being signed in. This is then showing the calls as abandoned when they were actually answered outside the queue and I can no longer tell how many calls are truly abandoned.

Thanks,

Rochelle