Geometric Sets have no order, and are very flexible because of this. If you want surface entities to behave like solids as far as ordering is concerned use ordered geometric sets.
creating structure in goemetric sets is the users responsiblity. use parents and Children, Design graph (may not be called this, but I cannot remember its exact name - On the tools tool bar in gsd), Change geometric set, insert geometric set, insert element (may not be called this, again I cannot remeber its exact name - On the tools tool bar in gsd), replace, hide/show, mask, etc.. To understand and create/modify/display the structure is geometric sets.