In next bot release you will be able to put amount of point, to be more precise, when u host a game while you are in lobby you can put !rating 1400 and no one below that rating will not be able to enter your game. Or if you want you can put !rating 300 and everyone with rating from that amount of points will be able to join your game.
When season starts everyone will have 1500 amount of points, and if you lose from someone who have bigger amount of points than you, you will lose less points, if someone have smaller amount of points than you, you will lose a lot of points.