Parents/Players – In order to receive texts messages/alerts you need to create a FREE MyLeagueUp Account. Note, please see the box on the left side towards the bottom of this page, you can sign up there. There is also a box that says "Game Cancelled" you can click on that as well.
I was able to add my line as well as Megan's on the same account. Not sure how many numbers can be added on one account though.