Special Game

There is a group of $N$ people. They have special rules for a special game : - There can be $M$ number of teams in a single match. - In each team, there are exactly $N/M$ players. They all want to play the game and they also want to oppose every other member of the group at least once. They can form a team of any possibility. Can you find the minimum number of matches they have to play? ###In