You can try to create two display groups and set your x, y properties to place them where you want on the display. Then you can write code to manage objects in any display group. Right now, I'm working on a game in Corona sdk that has four display groups. This gives me the flexibility to move all objects in a group by changing the x, y properties of a particular display group. In addition, you can insert display groups inside other display groups, so there are all sorts of options. In my game, background scrolls. Since all the objects for the background are in the display group, I can scroll all the objects at the same time, instead of scrolling them individually.
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