Count if a column record is unique

Hi – I’m building a Street Team in one table in Airtable. One view shows “assignments” which plots out what concert each street teamer is working on. Once they are done, they submit an Airtable form with their name, photo proof & the concert they worked on. This goes into a “review” view, which allows us to review to make sure they did the work.

Since “Assignments” (generated by us) and “Review” (generated by the worker) need to match, I’m trying to figure out a way to match them. So if we assign Street Teamer A to work Concert X, then we need to know when Street Teamer A submits their proof for Concert X.

So I created a match code field with the formula {name}&" - "&{concert}. In the example above, we’d know it’s a match because both OUR assignment AND their submission have the same match code (StreetTeamerA - ConcertX, in this example).

But how do I write a formula that then can determine whether that Match Code is unique? Meaning, if there is more than 1 of the same Match Code, then it displays “Yes”.