Telligent.Evolution.Controls.GroupSortableListControl

Hi we like to have list of groups from a predefined parent group in the selections 

<property id="groupSelectionCustom" resourceName="GroupInclusion" controlType="Telligent.Evolution.Controls.GroupSortableListControl, Telligent.Evolution.Platform" dataType="custom" key="group" sortPropertyId="sortByCustom" sortPropertyOn="containeridsorder"  sortPropertyHide="sortOrderCustom" />

 on this control we specified parentgroupid="3" so that it will take all subgrouops of group 3 , but it always working with the context , how can we define predefined parentgroup on this control

we are not getting any documentation reference to Telligent.Evolution.Controls.GroupSortableListControl