Optimize Report: Show instances having only one active token

Hi,
in Camunda Optimize (v. 3.13.7) I created a report to get me all instances that contain an active token on a specific activity. So far so good.
Now I want to filter this list (adapt the report) to only show me instances having one token at all.
So I want Instances that contain only 1 single active token and this token should be on a specific activity.
How can I do that?
Thanks in advance!