You could try the following:

1) Create a Transparent box in the background (set its ZIndex to 0)
2) Assign to its BoundingRect the union of all subordinate nodes rectangles + the current master node
3) Group all nodes to it, including the node you currently use as a master
4) Lock all subordinated nodes

Now if you click on any of the subordinated nodes, the invisible master node will be selected and moving it will move all attached items.

I hope that helps,
  Stoyan

This one creates a group of nodes like the described above:

https://mindfusion.org/_beta/Switch.zip

It's in VB.NET; you can create the group by double clicking.

Stoyan