Is there a way to access the spreadsheet or data from the spreadsheet that a Jotform populates in the form itself?

I would like to track registrations and close registrations for a session when it is full. the only way I can think of doing this is to check the count of current registrants in when a form is opened and then if there are no openings HIDE the session. Is that possible?

If I understand correctly, you want to have a registration that will display the amount of registrants and close it once the registration is sold out? Perhaps the ticket purchase widget would be suitable for your form.

http://widgets.jotform.com/widget/ticket_purchases 

You can check out the demo here: https://form.jotform.com/60130611186949

Perfect! Thx. Exactly what I needed.