Hi, yes. Shouldn't be any problem and you don't have to use any delegate approach either. If you as an organizer (receptionist) schedule a meeting, you simply only need to add the doctor and the third-party (patient) to the invite, and then go to the "meeting options". 1) Select to only let people in your organization to bypass the lobby (assuming the patient address/account isn't part of your org.) and then 2) add the doctor to the "Who can present" -> "Specific people" - > "Choose presenters" -> "Doctor". Save.
With these settings the receptionist doesn't have to be present. The doctor can start the meeting and is added as a presenter with almost all permissions as an organizer and can let the third-party in from the lobby as the patient will end up there. Perhaps use the chat option with "in-meeting only".