That would certainly make it more plausible, although the explanation would need a little work. Perhaps for every student of the new class, two teams were chosen to be a joint group, under two sensei of course, because of the international threat and whispers of war. 

That way the two teams aren't bunched together and forced to be in one squad, which would make the Exams and similar things more complicated.

Edit: Just me throwing out ideas. The end result is all up to the Boss, of course.