title: Sonata admin dynamic admin list due to sortable
body: <p>Please advise with the best solutions for such a task:</p>
  
  <p>Entity hierarchy: <strong>Department -> Category -> Product</strong></p>
  
  <p>Currently in Category admin I have a list of ALL categories for ALL departments. BUT, I need to implement ordering feature for categories, which is done with Doctrine Sortable, so I'm having moving arrows in admin list view. BUT, because positions are grouped by Department of category, I have multiple "first" and "last" categories and moving is not that clear (since I cannot post images yet):</p>
  
  <pre><code>1. category [move down]
  2. category [move down]
  3. category [move down][move up]
  4. category [move down][move up]
  </code></pre>
  
  <p>So, I added a default filter by department and now have shorter lists of categories by department. This has a lot of problems further on, so I'm looking for a better symfony/sonata/something else solution for:</p>
  
  <p>Separate (dynamic) admin/list of categories by same department (same thing happens with products by category).</p>
  
  <p>PS. Subclasses is not the solution, because I have only one category entity class, obviously.</p>