<script type="text/x-handlebars" data-template-name="gigs">
<div> // code simplified
    {{#each controller itemController="gig"}}
        {{#view App.GigView contentBinding="this"}}
            <div class="tile">
                <img {{bindAttr src="photo_url"}} />
                {{#if widgetDisplayed}}
                    // widget view
                {{/if}}
            </div>
        {{/view}}
    {{/each}}
</div>
</script>

App.GigsController = Ember.ArrayController.extend({
  anyWidgetDisplayed: false,

  isAnyWidgetDisplayed: function() {
      return anyWidgetDisplayed;
  }
});

App.GigController = Ember.ObjectController.extend({
  needs: ["gigs"],
  widgetDisplayed: false,

  displayWidget: function() {
    console.log(controllers.gigs);
    if (!controllers.gigs.isAnyWidgetDisplayed) {
      this.set("widgetDisplayed", true);
    }
  }
});