title: Create multiple lists of unique entries from master list in c#
body: <p>I need to process an outbound SMS queue and create batches of messages. The queued list might contain multiple messages to the same person. Batches do not allow this, so I need to run through the main outbound queue and create as many batches as necessary to ensure they contain unique entries.
  Example:</p>
  
  <pre><code>Outbound queue = (1,2,3,3,4,5,6,7,7,7,8,8,8,8,9)
  </code></pre>
  
  <p>results in...</p>
  
  <pre><code> batch 1 = (1,2,3,4,5,6,7,8,9)
      batch 2 = (3,7,8)
      batch 3 = (7,8)
  batch 4 = (8)
  </code></pre>
  
  <p>I can easily check for duplicates but I'm looking for a slick way to generate the additional batches.</p>
  
  <p>Thanks!</p>