How do I create a online score for player, and group?

Hi, i need the following feature.

I have a game that works with scores, each score should be to a player. This player pertain an a group that have a global score result of sum of all players.

The idea is confront some groups to fight for the maximum score (like alliance). Each alliance have X player that to get your score tha collaborate to alliance.

This feature should be make to save the scores online not local.

Its similar to google play, where each player put her name and begin to play.

How can i do that?

Thanks you!