Use autofilter if data in 2 columns

[basketball]

Dear members!
I've a game schedule where I do the referee nominations - please see the file
I want to be able to filter the columns gym, date and referee. I know how to do that on gym and dates, with the Autofilter. My problem is the referees, because the same referee can appear in bot columns referee 1 and 2 . Can you suggest any solution to this problem?
My second question is: I want to list each referees partners, thought to solve this with Pivot table - is pivot table the best solution, or du you have any other solution?


Thanks in advance for your help
Peter

file: https://www.dropbox.com/s/p798eq4u89fjxvk/english.xlsx?dl=0