just check their history in previous games. 3 of them they play only private games. 1 plays some open. And the one that has highest ranking plays regulary open and private with the rest. Also after 1000+ games check their medals.....
Game number(s): SOME of their games... because they are a LOT and winner changes for having equal scoring 9624031 9624027 9444507 9358193 9358187 9220506 9220501 9126122 ...