Howdy! I have a subscription service and am trying to figure out if there are any nice ways to to only allow active paying subscribers to book time. E.g. only allow approved email addresses or domains to book. The easiest solution I can think of right now is to just hide the booking page behind a subscriber/member paywall, but that's not great. It would be neat if there was some integration for a CRM/GoogleSheets/AirTable or something. Has anyone come up with solutions for this before?