Create a group
Invite outside the school
Moderate
Join by invite only.
In this scenario you want to crate a Google Group for a Book Club and allow other students from outside schools to join. Groups allow you to create a 'wall garden' - a safe space for only invited users to collaborate, teach online social interaction skills, and be able to moderate the discussion.
1> Go to groups.google.com
2 > Create a new group.
3 > Select settings - only invited members; message moderation,