Let's say I start with the default Blender (2.64) file, except I set the cube to be 1 for all dimensions. At that point, the cube is at xyz location (0,0,0).
Then, let's say I select the cube with right mouse button, and go to Object / Group / Create New Group, and confirm the name "Group" in the "Create New Menu" bar with [Enter]. The selection outline turns green, meaning it's a group "master" (as far as I can see).
Now, let's say I press Shift-A; and choose "Group Instance" > "Group", and set the new instance to Z=2.3; with all selected, the view looks something like this:
Now, let's say I deselect all with A, then select the group master with right-click; and let's say I move it to Y=-2; then the result is:
... that is, it is noticeable that the group instance/clone also moved in respect to its center (note the group instance axes, which remain in the set position)! Which means, I guess, that groups are defined in respect to the global coordinate center (0,0,0) as anchor.
My question is: is it possible to define a group, but in respect to the, say, bounding box center of the group as anchor - such that when I move/translate the group master, the group instances would remain anchored at their set position (basically, at the center of the group instance axes)? Also, is this documented anywhere in Blender documentation (I had problems finding this info)?