Um, that doesn't work at all. ;o)  However, I got a very weird result. :oD

I did a simple test with one mesh by centering it inside a flattened cube so it would show on both sides.  Changed the cube to positive and the mesh to negative and set the "solid when..." tick.  Grouped them and voila! 

One side of the cube has the top part of the mesh, the other side has the bottom part.  And it's not an even division either...it's rather jaggy.  Too weird. ;o)  It was a good try tho'.  I'd forgotten all about the "solid when" thing.