title: Muliple Lists inside a single ListView
body: <p><strong>Pre-info:</strong>
  I have a page in an app with a setup like this:</p>
  
  <pre><code>&lt;ScrollViewer&gt;
      &lt;ListView&gt;
          //Some Grids and simple layout
      &lt;/ListView&gt;
  
      &lt;ListView&gt;
          //Huge nested ListView containing another ListView
          &lt;ListView&gt;
              //Further nesting with grids and layout
          &lt;/ListView&gt;
      &lt;/ListView&gt;
  
      &lt;ListView&gt;
          //Some Grids
      &lt;/ListView&gt;
  
  &lt;/ScrollViewer&gt;
  </code></pre>
  
  <p>I use MVVM and the object's I am using to bind are at it's most simple something like this:</p>
  
  <pre><code>public class Activity
  {
      public string Description { get; set; }
      public IList&lt;NotImportantClass&gt; NotImportantClass{ get; set; }
      public string Comment { get; set; }
  }
  
  public class BaseClass
  {
      public string Title { get; set; }
      public IList&lt;Activity&gt; Activities { get; set; }
  }
  
  public ObservableCollection&lt;BaseClass&gt; BindingSource
  </code></pre>
  
  <p>I am developing the app for UWP and the performance with nested ListView's are horrible. After debugging with the elements from the server it is above 4000 elements that are placed out.
  I did read something about grouped ListView for WPF, but most of the lecture and articles I have seen just approaches it with one List and uses a key based on that.</p>
  
  <p>The Title-property can be used as a key, I just need some smart way to use linq or something to use Grouped ListView. Any suggestions on how I can approach this?</p>