hi!
This plugin is not able to integrate into other forms. It simply adds a widget to anywhere on the site that can display a widget.
Perhaps a way this could work for your users, is that they must fill out 2 separate forms: 1 Gravity form and 1 Sendy widget/form. You could add a required checkbox to your gravity form that says something like “I have subscribed to the mailing list via the subscribe form on the right”? this would be similar to the idea of requiring someone to check a box indicating they agree to the Terms of Service.
Hope this helps!
