Prebill filters for clients with balances but no activity

Our monthly prebill has grown to almost 800 pages, and I've been asked to separate it into clients with current billable slips and clients with balances but no activity and everything but current slips.  I've created a new prebill report for clients with current slips, but can't figure out how to filter for only clients with balances but no activity.  Outside of manually selecting these clients, which would take forever, is there a simpler way to do this?  I've tried filtering every which way to Sunday, but still don't get the report I need. 

We are using Timeslips 2015.  Thanks in advance for any help!