In sufficiently large schools, courses are given to classes in sections of various sizes. Consequently, classes have to be split into various given numbers of sections. We focus on how to dispatch the students into sections of equal size, so as to minimize the number of edges in the resulting conflict graph. As a main result, we show that subdividing the students set in a regular way is optimal. We then discuss our solution uniqueness and feasibility, as well as practical issues concerning teacher assignments to sections and the case of an additional course with unequal section sizes requirements.