Third Party [Photon] Method that runs on the server

I need to create a system to choose a random player, that is, a function that runs on the server and not on the client side.
Basically I need to select a random player and send that player to customers (so they will know which player was chosen)
It's running inside a room
I tried to use the masterClient with RPC, but the results were not good.

 

There always is a master client. It can be used to select a random player.