Restricting the number of registrants in a categor

Hi Folks,

so here's what I want to do:

I have the ability for people to register themselves and assign themselves to a team. Let's call them Orange, Blue and Red. I want each team to be no bigger than 50 people. Can I somehow close down registration for a team when the count has reached 50 and reopen if a user decides to pull out by deleting themselves? Also, could controls be implemented to increase team number?

Thanks!
Tobias

If you're using CBSubs to provide the teams you could use a CB Query Field to count how many users are actively subscribed to a plan via database query then on the Workflows tab of that plan create a conditional to check that the field is below 50.