Here's what I did.
1 - create NEW contact for each of the person if they are not yet in your list.
2 - with the calendar highlighted, click -> FILE -> Share ->
Share this calendar
3 - a wizard will pop up, click NEXT, click ADD
4 - select person you want to share the calendar with and click -> to put them into the box on the right
5 - click OK
6 - and now do this person by person to assign permission,
highlight a person, click PERMISSION
7 - after you have done this with all of them, click NEXT, click FINISH
8 - and you are done, an email will be sent to everyone with
a ACCEPT and DECLINE button. If they accept, a copy of your calendar will be automatically create in their folder list.
Hope this helps.