Out of the box, your best bet is going to be the Queue Service Level report. It will show you SL1, SL2, SL3... etc for each workgroup. But if I'm understanding the ask correctly, it isn't going to be your silver bullet.
Ensure that in your Tracker configuration in IA, that "Track Exception Routing" is enabled. Once that is enabled, have a look at the EE_TransferEvents_viw & EE_FlowoutEvents_viw in the database. It will give you the source queue, destination queue, and TimeInSource queue information, by InteractionIDKey. You can use that to determine how many interactions are going from queue to queue if they are flowing out or if users are transferring them, and tie that data into your workgroup stats to get a number that is a little more meaningful to your organization.
Thanks,
Trent.