How to conditionally trigger a Zapier integration between JotForm and ConvertKit

I have Zapier integration between Jotform and ConvertKit, what I'm wanting to find out is how to set this up so that every email isn't Zapped. We have a "would you like to sign up for our newsletter" click box on our Jotform forms. Right now, having that option clicked or unclicked makes no difference as far as the email being transferred to ConvertKit. That's not ideal.

I'm afraid that there is no way for us to control the Zapier zaps from our end. I see that Zapier currently only supports new submissions as its zap trigger:

You may want to raise a feature request with Zapier for allowing conditional rules in your zaps, such that would allow a zap to be triggered only when your field for newsletter is set to yes.

One alternative thing that does come to mind, but it would unfortunately require hiring a third party developer to help set it up for you, could be to submit your JotForm form submissions to a PHP page on your own website.

Then, you could programmatically check the received data directly on the custom PHP page, and if submission contains "Yes" in the newsletter question, then pass it along to Zapier in a webhook trigger. Here are the guides that may help with setting it up:

http://www.jotform.com/help/213-Send-POST-Data-From-JotForm-Using-PHP-in-Custom-Thank-You-Page

https://zapier.com/help/webhooks/#supported-triggers

I hope this helps.