How do you report on tasks that only have a team assigned?

I'm trying to find out if it's possible to report on tasks that only have a team assigned (no individuals). Obviously you can filter on the Assigned To {team name} - but I don't know how to include tasks with only the team assigned. Is there a way to filter for an exact match on the assigned to team, or perhaps a way to count the number of assignments so that it must be only 1?

Any ideas would be appreciated. Thanks-