How to find out the nodes that write to a storage pool

There is a legacy TSM environment in our company. It works farily good, but we are about to migrate some of major TSM clients to EMC NetWorker domain with a view to decommission TSM installation as a whole. There are a number of storage pools with 5 years retention period. We are anxious to know that nodes write to these pools. Our aim is to stop these pools from populating with new backups. The problem is we don't really know that management classes are used for each node. It is determined on the client side. Is there any sql query or command that shows the nodes that write to a particular pool?

Thank you very much in advance. Your help would be really appreciated.