Note: This options is enabled only if the "Enforce Group access to Subjects" is enabled  in the Group Settings Screen

The Set Groups for a subject Screen is accessed from the Subject List accessed from the Edit Subjects Menu option. 

Displays a page that allows the selection of the Groups that the access to the selected subject. Select the Groups from the right hand side and move to the left to allow subject access,

The OK button Saves the changes. 

NOTE: It is also possible to add group access via the Group Settings Screens