Birth particles on shape surface?

[mitchfx]

This is probably very simple and I'm just overlooking something obvious.  I'm trying to figure out how to birth particles on the surface of another particle shape (particle with geo).  I also need to then attach those new particles to the shape surface at birth.  Ideally I would like to do this also with a cloth shape, as well as limit the birth to a certain region of the surface based on either a map, matID or selected faces on source geo.  Any ideas?