Random Opening Arrangement in Curved Facade

I am trying to create a randomized arrangement of window openings for a facade using grasshopper but am unable to completely figure it out.  I have three window sizes (A,B,C) that must fit within a structural bay in either an (A,A,A), (A,B) or (C) arrangement. the facade is curved and I am having trouble getting the three different configurations to attatch.  I have only successfuly been able to get one type to attatch.  Any suggestions?  I have also created something similar to what it needs to end up like by manually doing it in rhino.  However, it doesnt randomize enough.