how to implement Fling on group

问题

I want to fling some images after some animations on them are over, and the animations run inside a window:

The red one which is above the other one, what I tried is:

if (xDn - xUp > 0) {
    Timeline.createSequence()
    .beginParallel()
    .push(Tween.to(GBMImage, SpriteAccessor.X, 0.2f)
    .target(170f))
    end().start(tweenManager);

}

where xDn and XUp are ontouchDown and ontouchUp x values. To move the image left and right. Now the problem is on left, fling image goes over the back window, which I want to go beneath the red window. Secondly the above code is working for single image, I'm not able to understand how to apply it to group,

来源：https://stackoverflow.com/questions/20604795/how-to-implement-fling-on-group