How can I make payment items mandatory based on a previous feild

I have three teams paying registration on the form but only one team MUST purchase other items.  How do I make those items mandatory for that team.

kar

You can use conditional logic Enable/Require field option, to make your payment field required based on user selection.

https://www.jotform.com/help/367-How-to-Make-a-Field-Required-Based-on-Another-Field-Selection-or-Input 

However if you want to make only certain products of your payment field required, unfortunately that is not possible to achieve. If payment field is required your users will be able to select one or multiple products. For example they can only select "2016 - 2017 Season Registration" option. It is not possible to force them to select other products as well. 

Possible workaround would be create your products outside of payment field using, for example dropdown fields. Then you would be able to make all fields required with conditional logic. However you would also need to perform calculation inside of the form and then to pass calculation to payment field. 

How to Perform Calculation in the Form

How to Assign Calculation Value

How to pass a calculation to a payment field

Hope this will help. Let us know if you need further assistance.