'Varchar' ]; private static $has_many = [ 'People' => Person::class . '.MultiRelationalGroup' ]; private static $default_sort = '"Name"'; public function getCMSFields() { $fields = parent::getCMSFields(); $fields->replaceField( 'People', GridField::create( 'People', 'People', $this->People(), GridFieldConfig_RelationEditor::create() ) ); return $fields; } }