Now we add three groups to our Confluence instance: "X", "Y" and "Z". All groups are assigned as normal extranet users (not User Manager). Group "X" is assigned to extranet "1", group "Y" is assigned to extranet "2". Group "Z" is assigned to both extranets "1" and "2".
Restricting and sharing a page is only possible for groups that are assigned to the current extranet space.
The groups created by the Space Privacy plugin, so called managed groups, can not be used for these actions!
As the table shows, a page in extranet space "1" can be shared with group "X".
Pages in extranet "1" and "2" can be restricted to group "Z".