Hi Scott,
Thanks so much for reaching out and for your interest in our products!
In general, Event Tickets Plus is built to integrate with WooCommerce and Easy Digital Downloads. You do have the option to install a WooCommerce extension, like this one, which can help you to integrate other payment gateways as well.
If this functionality is a requirement for your intended project and the above recommendation isn’t what you are looking for, I’d suggest that a third-party developer would be the best way to make this feature happen on a short timeline. ? We maintain a list of developers who work with our plugins on our Knowledgebase here:
https://theeventscalendar.com/knowledgebase/find-a-customizer/
Please let me know if you have any other questions on this topic!
Thanks,
Jaime