title: Celery chains of groups feeding groups
body: <p>My question is similar to <a href="https://stackoverflow.com/questions/13271056/how-to-chain-a-celery-task-that-returns-a-list-into-a-group">How to chain a Celery task that returns a list into a group?</a>, which basically asks how do we do:</p>
  
  <pre><code>process_list = (get_list.s(10) | group(process_item.s(i) for i in ???))
  </code></pre>
  
  <p>and the answer was to fake the group with a task. Now, an issue arises if want to extend the chain beyond the last group:</p>
  
  <pre><code>process_list = (get_list.s(10) | dmap.s((process_item.s(i) for i in ???) | do_something.s())
  </code></pre>
  
  <p>Then <code>dmap</code> returns <code>GroupResults</code> which cannot be processed by <code>do_something</code>. Any ideas?</p>
  
  <p>PS: The <code>dmap</code> solution will work only with the <code>pickle</code> encoder and not with the new standard <code>json</code> encoder.</p>