Office 365 Groups comes with a real Exchange calendar, but accessing a Group calendar is a bit cumbersome via the Outlook 2016 client. Figure 1 highlights the important steps. You first have to expand the Groups listings in e-mail view, select your group, and then click the calendar button in the ribbon. This is a different experience than clicking the calendar view and then the calendar.
Figure 1: Expand the Groups (left side), select the group, and then in the ribbon at the top, click the Calendar icon
When clicking the Calendar button, a new window opens. In the new window locate your group in the folder navigation pane, right click the group and pick Add to Favorites…
Figure 2: Locate your group, right-click the group and choose Add to Favorites from the drop-down window.
If you go back to the original Outlook window, click to view calendars in the folder view, you should now see your Group calendar in the My Calendars list, much more accessible.
Figure 3: In Outlook in the My Calendars list, you should see the favorite that you just added.
I hope the Groups navigation experience towards the different services proliferate into all contexts and apps over time, but for now this is as good a workaround as any to have Group calendars appear side by side with your other calendars.
Want to remove the calendar? Use the same approach, but Add to Favorites has turned into Remove from Favorites.
You can read Mikael’s original blog post and get other great tips on his blog site here: http://www.techmikael.com/2016/06/how-to-favorite-groups-calendar-for.html