>> easy answer for now - create the group at the origin before you move the cube
I think I tried that. The problem is that I don’t want the original group at the origin and so when I move it, all instances of the group also move by the same amount.
I think, however, that I have discovered the way Blender wants me to approach this sort of need: use a separate Scene for each group you wish to instance.
- Start with an empty blender project (delete the cube)
- Add a new empty Scene to the project (select ADD NEW from the Scene dropdown of the User Preferences header (aka the bar containing the File menu etc.)
- In this scene add a cube at the origin and put it in a group called foobar.
- Switch back to the main Scene and add an instance of foobar (Add->Group->foobar)
Since the foobar group was created at the origin, (in your separate scene), it will have the transform manipulator in the correct position and the object data will be nicely centered where you had the 3D cursor. Everything is happy.
Alternatively you can Append or Link in the group from another file rather than using a separate scene but the same rule applies: your group should be at the origin.