Outlook has the ability to have more than one Calendar within your Mailbox.
To create an additional Calendar within your Mailbox, click Home > Open Calendar > Create New Blank Calendar.
Figure 1: Create new blank calendar command
Name the Calendar and pick what folder to place it in. For this example, I will be creating a Calendar named Test Calendar and I will put the
Calendar directly in my Mailbox. When finished, click OK.
Figure 2: Name new Calendar
Notice that the new Calendar appears in your calendar Navigation Pane.
Figure 3: New calendar in navigation pane
Also notice that when viewing the folder list within outlook you now have this Calendar listed.