title: GroupBy with multiple attributes in angular filter
body: <p>I have the json data like below 
  <code>[{
      "id": 1,
      "address": "MG Road",
      "country": INDIA,
      "state": AP,
      "city": VIJ
  },
  {
      "id": 2,
      "address": "Miyapur",
      "country": INDIA,
      "state": TS,
      "city": HYD
  },
  {
      "id": 3,
      "address": "Autonagar",
      "country": INDIA,
      "state": AP,
      "city": VIJ
  },
  {
      "id": 4,
      "address": "Kukatpalli",
      "country": INDIA,
      "state": TS,
      "city": HYD
  },
  {
      "id": 5,
      "address": "Koti",
      "country": INDIA,
      "state": TS,
      "city": HYD
  }
  ]</code></p>
  
  <p>I want to display like below format</p>
  
  <p><strong>IND,TS,HYD</strong><br>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Miyapur,Koti,Kukatpalli <br>
  <strong>IND,AP,VIJ,</strong><br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;MG Road, Autonagar</p>
  
  <p>For that im using groupBy filter like below but i was unable to group those values</p>
  
  <p>here is my code</p>
  
  <pre><code>     &lt;div class="location-container"&gt;
              &lt;label ng-repeat="(key,value) in locationmodel | groupBy: '[country,state,city]'"&gt;{{key}}
              &lt;/label&gt;
              &lt;span ng-repeat="location in value"&gt;{{location.address}}&lt;/span&gt;
        &lt;/div&gt;
  </code></pre>
  
  <p>But with above code i was unable to get what i'm expected. please help me in resolving this.</p>
  
  <p>Thanks in advance </p>