We have a Distribution Group in O365, which contains all members of a team. When you add this Distribution Group to the calendar, you can see the calendar of each team member. This way the admin can just update the Distribution Group with new team members, and everyone has gets the updated list of calendars.
In the current Outlook you need to disable "Turn on shared calendar improvements" for this to work as described here.
But in the "new" Outlook I can't add the calendars via the Distribution Group, and the option from the "old" Outlook is gone.