Limit online bookings for patients who have not been in for a determined period of time.

I have patients booking in for an adjustment online that have not been in for long periods (more than 12 months) and typically they come in with a list of new problems. This is not appropriate for a regular adjustment and needs to be made a longer duration as a ‘re-exam’ for example. I want the ability to limit the patients ability to book, based on the last time they were in…