I'd think that they probably pull the names out of a hat, eliminating that problem, but I'm not sure. Though I kind of figure that the problem would occur in different Clans if they share a bloodname, or have the same bloodname but through a different bloodparent(Jorgenson for the former Widowmakers and Ghost Bears, and Cooper for Hell's Horses and Snow Ravens would come to mind. Hmm, I wonder what would happen in the later case if each one had a Star Commander named Lauren from House Cooper? :o )