I am using MS Office Outlook 2013.  When I go to Mail>Account Settings, it says my e-mail account "type" is Microsoft Exchange.  We subscribe to Office365 and this service supplies us with Exchange server.  As a matter of fact, I have shared calendars before and I have had calendars shared with me.  

In the calendar view of MS OUtlook, I have a list of several calendars that I have created.  There are only TWO once called: Calendar, the other called My Calendar that have my MS Exchange e-mail address out to the right of them. Like:  "My Calendar  sample@microsoft.com"  These are the only two calendars that I can shared.  If I click on another calendar such as "Off TIme", in the Folder Tab, the Share Calendar button is "greyed-out" or unavailable.

How can I create additional calendars that are shareable? Ideally, I would like to be able to share other calendars that I have already created that are already in my calendar list