Team Makers has 7 sites in Fargo/WF, including the Dome and Scheel's Center, out of some 70+ sites in the market. So they don't dominate, although they have some prime spots in Lucky's, Frank's and the Holiday Inn. (They don't have Herd n' Horns, Legion baseball does. I thought that was funny.)
In Grand Forks, the organizations with the most sites is Development Homes, with 9 sites, and LISTEN, with 7. The Blue Line Club has 3, and GF Youth Hockey 5.
BTW, REA has a gaming license. Their only site is the arena, so I assume they need it to do the 50/50.