How do I make team system in multiplayer game

I used instance variable size and color to set size and animation name (color) for each Peer.

How do I make my game detect if Peer sprite is overlap with another Peer and if they have

different color game will subtract size of both Peer?

It seems quite confused what you want to do, can you explain it? Do you want to make a game like the Agar.io

You can create another variable life for the current player.

With color variable you can assign a number to it, so if the color variable is different from the player's team color, then reduces size and -1 of life when life is less than or equal to zero destroys the player and end game.

Thank you for reply sielxm3d and Yes I want to make game like Agar.io