do you need to create child?
Or it's enough to set child visible? This way you can bind visible property of child to selected property of radiobutton and don't need states.
If all your state is doing is handling the display of a radioButton group, then I would simply manipulate the visibility of your group instead of using the memory intensive state.
I know this could be handled easily by binding the visibility of the new component to the radio button group.
But the requirement states that a child be created...
If so it's easialy to create components using AS.
You can set properties with transistions there you can set visible true/false and includeInLayout true/false depending witch grid you want to view.
Or you can try using the ViewStack component.
If you must use states I guess you would have to create THREE states, one for showing left child, one for right, one for both?
Well, I guess I was stuck on States then. Setting the includeinLayout and visible properties for these components did the trick for me.