as i note below, events that fire on a model also fire on the collection. so: 

```
this.listenTo(this.model, 'change:active', this.renderCollection);

renderCollection: function(model) {
   this.without(model).each(function(m){m.set({active: false})};
}
```

or something to that effect. there might be an ordering problem because you want your models to render AFTER the state is set.