Grouping Object in Different layers

Grouping object in different layers in Inkscape will bring them up to the layer of the highest item in the selection. In figure 1, I draw 3 circles, the red one in first layer, green second layer and blue in third layer. When I group red circle ( layer 1) and blue circle (layer 3 ) together, the result is in the top layer, see that the green layer is below the red layer in figure 2.