title: CoreData Fetched Property referring to a different entity
body: <p>I have a CoreData Entity named <code>List</code> it has a Relationship to an Entity <code>Address</code>. This is a one-to-many relationship seeing as an <code>Address</code> can be only be one <code>List</code>.</p>
  
  <p><code>Address</code> entities have an Attribute <code>flag</code> which is an <code>Integer 16</code>. </p>
  
  <p>Is there a way for me to define a <code>Fetched Property</code> in the <code>List</code> entity with a count of all related <code>Address</code> entities that have their <code>flag</code> set to 1? What would the predicate look like?</p>
  
  <p>Thanks</p>