ember.js concurrent substates?

gistfile1.js

var State = Ember.State.extend({});
var ViewState = Ember.ViewState.extend({});

// existing 
App.statechart = Ember.StateManager.create({
  loggedOut: ViewState.create({}),
  loggingIn: ViewState.create({}),
  loggedIn: Ember.StateManager.create({
    appLoadFailed: ViewState.create({}),
    appLoading: ViewState.create({}),
    appLoaded: State.create({
      enter: function() {
        // start up substates
      },
      exit: function() {
        // tear down substates
      },

      pushNotifications: Ember.StateManager.create({
        pushDisconnected: State.create({}),
        pushConnecting: State.create({}),
        pushConnected: State.create({}),
      }),
      displayAppUI: State.create({
        enter: function() {
          // start up substates
        },
        exit: function() {
          // tear down substates
        },

        displayUI: ViewState.create({}),
        displayModals: Ember.StateManager.create({
          displayNone: State.create({}),
          displaySettings: ViewState.create({}),
          displayWarning: ViewState.create({})
      }),
      backgroundQueue: Ember.StateManager.create({}),
    })
  })
});