Complex sentence: In this competition, a promotion-relegation format was introduced, with the winner of Division 2 replacing the loser of Division 1, and the winner of Division 1 replacing the loser of the Five Nations.
Split into simpler sentences: In this competition, a promotion-relegation format was introduced. The winner of Division 2 replaced the loser of Division 1, and the winner of Division 1 replaced the loser of the Five Nations.