Asterisk Round Robin Queues

We need a solution that will round robin callers to specific Queues When a keypress is pressed, the script will determine the last queue the call was sent to and send it to the next queue. There will be n number of queues and the script will need to be easily adjustable to add or remove queues. Queues will be held inside of extensions for ease of management. So instead of sending calls to a queue, you will send them to a custom extension that will include the queue and other potential processes. We are currenly using Fonality PBXtra with asterisk 1.2 core. However script should work on both 1.2 and latest 1.6 asterisk core.