Griz hockey already exists for men and women! This is their 3rd season. They are also partnered with GIR already and are playing Missoula League and in regional tourneys. The women's hockey team's first tourney of the season is this weekend, and games start in November.
I could not find a link for the mens team, but if you want to follow the Lady Griz on ice, check out their schedule at: http://www.umt.edu/womenshockey/
Frankly the facilities at Glacier Rink will need to be expanded or even moved to meet the growing interest and need in winter sports. Schools are adding more junior hockey teams, and Missoula Curling Club just added brand new lanes to the outside rink bringing in yet another regional sport using the same packed facilities. Just more people wanting time on limited ice.