In addition to allowing the customer to choose specific person vs no selection, there needs to be an option under Services to "force all staff" or "force selected staff" to be booked together for a Service. So the customer would only see appointment slots where 2+ Staff members, who were grouped under the Service, are all available. I.e. a "Required" checkbox next to their names in the service. This option is needed if an appointment requires more than 1 person. The booking would then go on all the Required Staff calendars. This functionality would make Bookings much more powerful allowing you to share whole groups availability with 3rd parties for scheduling big meetings without trying to coordinate across a dozen calendars. It would do what Calendly does, something sorely missing from Outlook 365 and desktop.