Disable submissions on condition of field chosen

I have tournament that allows submissions for 2nd - 8th grade teams to sign up.  i.e. after 16 teams of 2nd graders sign up, we want to cap the submissions.  

Is this possible and if so, please advise,

You can limit the submissions to your form in the Form Settings page. Here's a screencast guide:

If that is not what you're trying to create, please let us know.