Ember group binding

I'm looking for a good way to bind grouped objects and render it to the grid. Here's a grid example:

| League / Country | Canada | United States | Brazil | | 1 | John, Sam | | Tim | | 2 | Liam | | Robert | | 3 | | James, Peter, Tom | Den |

And Player's model

DS.Model.extend({
    name: DS.attr(),
    country: DS.attr(),
    leagueId: DS.attr("number")
}); 

What is the Ember-way to output list of players into such grid, so that it nicely bound and if I change country or league - player is rendered into proper cell?