Page-level permissions
Why to use page-level permissions
Page-level permissions allow you to set different levels of access for different people on different pages. For example, you could allow all your friends to see one set of pages, allow your family to edit another set of pages, and then keep yet another set of pages private only to yourself.
https://support.google.com/sites/bin/answer.py?hl=en&topic=1387383&answer=1387384&rd=1
https://support.google.com/sites/bin/answer.py?hl=en&topic=1387383&answer=1387384&rd=1
