It installed (activated), with errors. I changed "edit.php" to "file.php" on line 1209, that changed it from no functionality to partial with a different error message after each operation, "headers already sent in pluggable.php line 890." I can add and remove groups (with errors), but cannot add posts to a group.
Is the author planning or working to update this plugin? Has anyone found or written an alternative plugin with similar functionality?