(I’m still having a hard time reading your code, but at least it’s there. Code Formatting)
Note that the location of every Node (including any Group) is in document coordinates. So if a Group is at a particular location, you need to make sure that the node is there (perhaps with some offset) as well.
Please re-read Get Started with GoJS and the first dozen or so pages of the Introduction, starting at GoJS Introduction -- Northwoods Software. Note these two pages:
GoJS Data Binding -- Northwoods Software
GoJS Coordinate Systems-- Northwoods Software