We suspect that your requirement is, the Selector & Rotator should not be visible for the Group (for example, the group will not be shown visually) and also when we move any individual node in that group, the whole group should be move. Please refer the below suggestions.
1. To collapse the Selector & Rotator of the Group
We can collapsed the visibility of the Selector & Rotator of the Group by using the below code snippet. Now, the group selection will not be visible.
Code Snippet :
Group grp = new Group();
grp.Loaded += new RoutedEventHandler(grp_Loaded);
void grp_Loaded(object sender, RoutedEventArgs e)
Border border = (Border)VisualTreeHelper.GetChild(sender as Group, 0);
Grid grid = (Grid)VisualTreeHelper.GetChild(border, 0);
//Get the reference of Resizer of the Group
Resizer resizer = grid.FindName("PART_Resizer1") as Resizer;
//Collapse the visibility of the Resizer
resizer.Visibility = Visibility.Collapsed;
//Get the reference of Rotator of the Group
Rotator rotator = grid.FindName("PART_Rotator1") as Rotator;
//Collapse the visibility of the Rotator
rotator.Visibility = Visibility.Collapsed;
2. To move the whole group by using the individual child node of the Group.
By default, when we click any child node in the group, first the group will be selected and when we click again any child node in that group then only that individual node will be select. So, in this scenario, single click on any child node and drag that node, the whole group will be move. (Note : When we single click on the child Node, the group selection will not be visible because the Selector & Rotator of the Group is collapsed). For more information please refer the attached video.
For more information about the group, please refer our online documentation using the below link.
Documentation Link: http://help.syncfusion.com/ug/wpf/diagram/default.htm#!Documents/44groups.htm
Please let us know if you require further assistance on this.