Hi there,
Thanks for reaching out. I will try to help with your question.
If you are using WooCommerce as your ecommerce solution, then there is way to do this with our plugin.
You can create a custom template that will override the link markup that appears when logging in is required.
Copy event-tickets-plus/src/views/login-to-purchase.php to [your-theme]/tribe-events/login-to-purchase.php, and edit the link to point at your desired URL.
For more information about working with custom templates and our plugins, check out this article: https://theeventscalendar.com/knowledgebase/themers-guide/
Hope that helps! Please let me know if you have any additional questions about this.
Thanks,
Sky