I cheked their website. It says anyone can skate there for 1,300 yen a day. Members get to skate for 1,000 yen a day. It doesn't give you specific info about group use, but it says they rent to groups outside of their regular hours. So it should be worth making an inquiry directly.
http://www.citizen-plaza.co.jp/service/skate/index.html
The Seibu Prince Rabbits play all over Japan. I saw their schedule for last year, but it didn't look as if they played half of their games at the same place.
SEIBU PRINCE RABBITS ICE HOCKEY TEAM