You can do this with nested composite views. For the use case you described you could nest a compositeView for your Apartments and Rooms.
Fiddle:
http://jsfiddle.net/yCD2m/23/
Markup
<div id="apartments"></div>
<script type="text/html" id="appartment">
<div>
<h2>Apartment: <%=apartment%></h2>
<ul></ul>
</div>
</script>
<script type="text/html" id="room">
<h3><%=name%></h3>
<ul></ul>
</script>
<script type="text/html" id="chair">
<b><%=chairType%></b>
</script>
JS
var apartments = [
{apartment: '1a', rooms: [
{name: 'master bed', chairs: []},
{name: 'kitchen', chairs: [
{chairType: 'stool'}, {chairType: 'stool'}]},
{name: 'living room', chairs: [
{chairType: 'sofa'}, {chairType: 'love seat'}]}]
},
{apartment: '2a', rooms: [
{name: 'master bed', chairs: []},
{name: 'kitchen', chairs: [
{chairType: 'shaker'}, {chairType: 'shaker'}]},
{name: 'living room', chairs: [
{chairType: 'sectional'}]}]
}];
var chairModel = Backbone.Model.extend({});
var roomModel = Backbone.Model.extend({
initialize: function(attributes, options) {
this.chairs = new Array();
_.each(attributes.chairs, function(chair){
this.chairs.push(new chairModel(chair));
}, this);
}
});
var ApartmentModel = Backbone.Model.extend({
initialize: function(attributes, options) {
this.rooms = new Array();
_.each(attributes.rooms, function(room){
this.rooms.push(new roomModel(room));
}, this);
}
});
var ApartmentCollection = Backbone.Collection.extend({
model: ApartmentModel
});
var ChairView = Backbone.Marionette.ItemView.extend({
template:'#chair'
});
var RoomView = Backbone.Marionette.CompositeView.extend({
template: '#room',
itemViewContainer: 'ul',
itemView: ChairView,
initialize: function(){
var chairs = this.model.get('chairs');
this.collection = new Backbone.Collection(chairs);
}
});
var ApartmentView = Backbone.Marionette.CompositeView.extend({
template: '#appartment',
itemViewContainer: 'ul',
itemView: RoomView, // Composite View
initialize: function(){
var rooms = this.model.get('rooms');
this.collection = new Backbone.Collection(rooms);
}
});
var ApartmentCollectionView = Backbone.Marionette.CollectionView.extend({
itemView: ApartmentView // Composite View
});
apartmentCollection = new ApartmentCollection(apartments);
apartmentCollectionView = new ApartmentCollectionView({
collection: apartmentCollection
});
App.apartments.show(apartmentCollectionView);