I'm not certain I'm following the question correctly but to add additional fields to be filtered into a RCE report you can just drag the appropriate field from your available fields up into the filter section at the top of the report.
If you are missing a field that you would like to filter or report around from your available fields you can add more by going into Admin > Revenue Cycle Analytics > Custom Field Sync (tab) then from here click on a field and enable it.
For sent over 5,000 you'll want to filter on sent and make it Greater Than or Equal To.
Hopefully that's helpful. If not maybe I'll be able to explain better.