Keep Out: Restricted Google+ Communities Help Keep Conversations Private
Like the functionality of Google+ communities, but don’t want to expose your content shared to the world? Well now Google’s got a solution for you: Restricted Google+ communities. Companies will now have the ability to create invite only communities or restricted communities that are open to those with email addresses specific to a domain name.
This is an ideal solution for internal teams or specific projects as users can share files directly from Google Drive. Community owners can manage membership, change settings or invite others. The default setting for restricted communities will default to your organization, but users can keep restricted if access should be limited to specific employees.
For more information see the official Google announcement.