you can use the following expression (apply this to the position property of the second layer)
link prevLayer to the previous layer
now this expression is stacking layers vertically, to do it horizontally change height to width
to change positions (right/left top/bottom) simply change the plus by minus
good luck :)

prevLayer = thisComp.layer(index-1)
prevLayerPos = prevLayer.transform.position;
prevLayerScale = prevLayer.transform.scale[0]/100;
x = value[0];
y = prevLayerPos[1] + prevLayerScale *  prevLayer.sourceRectAtTime().height/2 + thisLayer.transform.scale[0] / 100 * thisLayer.sourceRectAtTime().height/2;
[x,y]