I know that I can set sharing permissions for an entire calendar. And I know that I can reduce the permission (i.e. increase the privacy) of a single appointment by marking it as "private". However, I haven't been able to find a way to do the opposite. That is, I'd like my calendar, as a whole, to be shared as "can view when I'm busy", but I'd like to also be able to mark an individual appointment as non-private, so that the person with whom I'm sharing the calendar can see all of the details for that particular appointment. Is this possible?