Creating a summary report with limited drill-down capability

I have a prototype dashboard with a graph that drills down to a Summary Report. It works now, allowing drill-down to see summaries by 3 groups in the source sheet (Division, Organization and Backup OK), which is great. However, in the current iteration it allows the user to drill down to the detail level of the source sheet, displaying the EMail field (which is the primary column on the source sheet).


A decision has been made that this level of detail is no longer needed and PII like Email should not be displayed, so I would like to have the exact same report grouped by Division/Organization/Backup OK fields (and expandable/able to drill down by multiple Div/Orgs), but but prevent the Primary Email Column of the source from being displayed/available.

Email is not selected or available in the columns selection (I guess because it is primary in the Source sheet). There are 3 similar reports based on different columns in the source sheet, so I can't really make the Backup OK field primary in the source sheet.

What would be the best way to accomplish this? I have tried various things with little success...

Thanks!

Answers