You could use an If-then-else column to say "if employee location is A, then show location B, then show location C, then show location D, else show location A.
You’d have to create an If column for each location (so if you have a ton of locations, this may not be the best approach).
Alternatively, you could set up your locations as an array and use a single value column to show them in the employee sheet. This would cause a duplication of the employee’s location (it would be in the main " employee location" column and again in the array of all locations). I’m not sure how a map handles two of the same location value.