Ember route with dynamic segment name

I'm just starting with Ember and ember-cli and trying to figure out this routing issue. I have a Group model that hasMany Game models. With the following route, I am able to display games just fine from a group URL:

Router.map(function() {
  this.resource("groups", function() {
    this.route('show', {path: ':group_id/show' });
  });
});

This results in a URL with the form:

    http://localhost:4200/groups/1/show

Suppose one of the Group names is "wizards". I'd like to to be able to construct a URL in the following form and render all the Games that belong to "wizards":

    http://localhost:4200/wizards

Any tips are appreciated.