Is it legal to forbid the singing of the National Anthem?

I'm a high school student, and because of the actions of a few, my entire school has had the right to sing along with the National Anthem taken away. A "small group" of students at a past game yelled "...and the home of the Vikings" (our school mascot), and because of them, no one can sing it any more. Is this legal, and what can be done about this? I've thought about contacting some local news stations or Shaun Hannady (who my mother believes would go crazy over something like this). Please let me know what you think and what you know.