I'm not explaining correctly. Let me restate.

The pivot table lets me see group membership fairly quickly based on the source data area. What I want to do is filter the data that is available to the pivot table using a list.

Lets say the full source data area contains hundreds of rows made up of perhaps 100 unique users belonging to up to 10 unique groups. That would be 1000 rows if all users belonged to all groups (but they don't). Suppose I'm only interested in the group membership of 10 specific users.

I know I can manually filter at the pivot table both the users (rows) and groups (columns) shown but I would like to use a list as in advanced filtering.

All of this is reference only. No data will be changed. If I determine group membership isn't as needed, I have to submit a request to add/remove users in AD. I have read-only access to Active Directory.