Yeah, grouped controls are painful to set up in the Edit Controls dialog. I usually just add a random dummy control to my tool, then copy and paste it into a programmer's text editor and set it up there. There's a good document in the old VFXPedia on the topic:
https://www.steakunderwater.com/VFXPedi ... r_ControlsIt's not
quite comprehensive, but it covers most of what you'd need. There's nothing in there about the Viewer controls or the Point control.