You may create and share multiple calendars, in addition to your default calendar. These calendars may only be created at the top-most folder level.
No subfolders may be created under the default Calendar folder.
From the top menu, select New->Folder.
In the Create New Folder window:
Enter a name for the new calendar.
Select Appointment Items in the “Folder contains” field.
Click OK.
The new calendar folder appears under the main folders list.
Your free/busy status does not include appointments and meetings scheduled in non-default calendars.
You may also share your non-default calendar and subscribe to another user's non-default calendar. See Sharing Your Calendar and Subscribing to a Shared Calendar for instructions.