title: customize 403 error page depening on route in symfony 2.0
body: <p>i want to customize the error pages in Symfony 2.0</p>
  
  <p>I know that this is done via overwriting the layouts in <code>app/Resources/TwigBundle/views/Exception/*</code> but I want to have different error pages for different routes.</p>
  
  <p>I want one for backend and one for frontend.</p>
  
  <p>How can I achieve this?</p>