I am trying to model a tripod. The idea was to model just one leg, making it a group, and then create two group instances of the leg, rotate them +-120 degrees (to face each other) and voila. The problem I have though is that once rotated the grouped instances no longer move in the same global direction as the original leg. Instead, after the rotation, if I move the leg along the x axis, the instances will move along THEIR x axis thereby breaking the tripod apart.
Set Transform orientation to Global, not Local. It seems that 3d manipulator widget confuses you and you drag with it.
You can move them along global axis also via keyabord - G > X and Rightclick Drag + X.