Fetching records and nested relations

I have a route in my app (repo) where i fetch bookings belonging to a user, I also include rentals and rentals.rental-ratings in the request. Now, a rental (which belongsTo a Booking) hasMany rentalRatings, and rentalRatings belongsTo Users. In the template I have a component that accepts booking and a rentalRating as arguements. How can I get a rating that belongsTo the booking and the currentUser?

Bookings route:

import Ember from 'ember';
import AuthenticatedRouteMixin from 'ember-simple-auth/mixins/authenticated-route-mixin';

export default Ember.Route.extend(AuthenticatedRouteMixin, {
  sessionAccount: Ember.inject.service(),

  model() {
    const currentUser = this.get('sessionAccount.currentUser');

    return this.get('store').query('booking', {
      filter: {
        'user_id': currentUser.id
      },
      include: 'rental,rental.rental-ratings'
    });
  }
});

Bookings template:

<h1>Your bookings</h1>