I use the Forms as an entry to our dog events for our club.

I use the Forms as an entry to our dog events for our club. We often have 2-6 potential classes that an exhibitor can enter. So, lets say I have 2 classes entered on a form. I need to know when the grand total of classes entered is 30. How do I or can I set up the "Disable" function to reflect that we have a total of 30 entries instead of 30 submissions? But, sometimes a competitor will only enter 1 class while the next competitor will enter 2-4 or more. Is there a way to do this?

Thank-you for your help.

Victoria

I'm not sure if I understood your question completely, but you may limit the selections with some widgets, example: 

https://widgets.jotform.com/widget/inventory

https://widgets.jotform.com/widget/gift_registry

https://widgets.jotform.com/widget/quantity_gift_registry 

This guide will help you adding the widgets to your form: https://www.jotform.com/help/252-How-to-Add-a-Widget-to-Your-Form 

You may also perform calculations and pass the amount to the payment field, here are the guides: 

https://www.jotform.com/help/259-How-to-Perform-Form-Calculation-Using-a-Widget

https://www.jotform.com/help/275-How-to-Pass-a-Calculation-to-a-Payment-Field 

I hope this helps.