Help with openings in geometry faces

Hi!

Im having problems creating openings on polyhedron's faces. Im attaching the definition where I have a polyhedron in which selecting a face I was able to create this opening like in the tutorial http://designreform.net/2011/03/rhino-grasshopper-parametric-truss-... but somehow this is not so simple when I start applying it to the rest of the faces.. The points selected to create the poliline that is then offset to make que opening space in the second face are not selected in order so I have to select each point with items (green Group). Does anybody know how to achieve what I did on the first face (purple group) but repeating it on all of the faces of this geometry without having to select each point individually??

A.