title: Synchronize 2 lists
body: <p>What is the best fastest way to Synchronize 2 Lists?</p>
  
  <pre><code>public class UserGroup
      {
          public UserGroup(string group, string user)
          {
              this.Group = group;
              this.User = user;
          }
          public string Group { get; set; }
          public string User { get; set; }
      }
  
  
  IList&lt;UserGroup&gt; userGroup1 = new IList&lt;UserGroup&gt;();
  IList&lt;UserGroup&gt; userGroup2 = new IList&lt;UserGroup&gt;();
  </code></pre>
  
  <p>Each group has different number of members.
  How can i find out the different and merge both in one new list?</p>
  
  <p>PS: I can change the type from IList to whatever if it would be more efficient.</p>
  
  <p>Thanks</p>