For interdivision matchups with odd number of divisions each with same even number of teams
Consider a league (or subleague) setup of 18 teams in 3 divisions of 6 teams. For the 6-team divisions the circle method could be used to set up all the divisional matchups with all teams able to play divisional games at the same time. The next step would be to lay out the interdivision matchups. But an odd number of divisions means you could not have whole divisions matched up against each other - if every team in division 1 is playing against a division 2 opponent, those divisions are covered, but division 3 is left out.
A solution is to break up the divisions into pieces and do the initial layout steps on those pieces rather than either by whole division or by individual team.
