title: LINQ: Dinstinct and merge values
body: <p>Supposing I have the following list</p>
  
  <pre><code>        var list = new List&lt;CustomClass&gt;
          {
              new CustomClass {Group = "Car", Color = "White"},
              new CustomClass {Group = "Motocycle", Color = "Blue"},
              new CustomClass {Group = "Car", Color = "Black"},
          };
  </code></pre>
  
  <p>How do I set this list to be distinct by Group and merge the Color with commas, such that my list will be:</p>
  
  <pre><code>Group            Color
  ------------------------------------
  "Car"           "White, Black"
  "Motocycle"     "Blue"
  </code></pre>