Of course, it is possible.


Go to Website builder > Navigation. Disable the Buy Tickets page, and Save.

This will make sure users can purchase tickets only when they log in to their dashboard.

Now, go to Settings in the top right corner, choose No for 'New user registrations are approved automatically' setting, and Save.

This will make sure users can log in to their dashboard only when you approve them. The login credentials are sent to them on registration but they cant log in unless and until you approve them.