title: Kohana 3.x ORM: Merging two different entities into one array ordered by timestamp
body: <p>I use Kohana 3.x and Im familiar with its Object-Relational-Mapping Modul.</p>
  
  <p>I basically have three different classes of items that I want to show on a users wall: ratings, comments, and updates. This three are completey different entities, but because they all can appear on a users wall, I just call them "wallitem". The all have a timestamp property, which represents the date they were created.</p>
  
  <p>I want to enable users to page through the wallitems, ordered by the timestamp. For example: last 10 wallitems. Or wallitems 20 to 30. How can I do that? I dont think there is an SQL-Query that could solve my problem.</p>