ember add an promise to a rsvp promise because of action

i have a route that returns several models as such

FriendEnemyRouter

model: function() {
    return Ember.RSVP.hash({
        friends: this.store.find('People', ...),
        enemies: this.store.find('People', ..),

On the same router theres an action (Its on the router because it does store 'things')

actions: {
     findMoreFriends: function(param, param) {
         var newFriends = this.store.find('People', ..); 
         var newPromise = this.controller.get('model'); //OK. Inspecting sees above friends and enemies. What type is it?

         model.set("newFriends": newPromise); // throws an exception
         //-- or --
         model.newFriends = newPromise; // no exception but observer (computer property) on the controller is not fired.
     }
 }

Ultimately i wish this computed property on the controller to fire

 FriendEnemyController

  computedNewFriends: function() {
       ....
   ).property('newFriends');

What is the procedure for adding new promises to rsvp promises...not even sure the object types...

         model.set("newFriends": newPromise); // throws an exception
         model.newFriends = newPromise; // no exception but observer (computer property) on the controller is not fired.