Complex sentence: The Premier and First Divisions will have 10 and 6 teams respectively while the Heartland Championship will also be reduced to 10 teams, that means that two teams from the current competition will be promoted to the First Divsion along with four Air New Zealand Cup teams.
Split into simpler sentences: The Premier and First Divisions will have 10 and 6 teams respectively while the Heartland Championship will also be reduced to 10 teams. That means that two teams from the current competition will be promoted to the First Division along with four Air New Zealand Cup teams.