I'm in the same sports boat as you Dana.. two options...
1. Google+, and you set up the groups/teams as circles. (We gave up on this.)
2. Rainedout.com (We have used this for 2 years now.) While not an app, it has worked very well for us. You set up your league, everyone else opts in if they want to (and they will since it is the best way to get time sensitive notices). We set up a couple admins, a 'board', the coaches, and individual teams as separate groups. This way you can broadcast to the league, or coaches can to just their individual teams. It's ad-driven so it's free. But there is now an option to pay a fee and drop the ads. We've been pretty happy with it. Good luck whatever you do.