I wrote an external application that needs permissions to Create/Delete items on all user's Calendars (that belong to a specific OU).
The application connects to Exchange 2013 by invoking EWS web service methods such CreateItem/DeleteItem/etc.
Furthermore, it authenticates against EWS 2013 with a single user. I need to grant this user the above mentioned permissions to all those calendars.
HOWEVER, this OU is constantly changing, adding/removing members, etc. I am trying to avoid doing this through a Security Group which I have to constantly maintain to make sure it's up to date.