title: Is is possible to filter on an OData navigation property?
body: <p>A USERS collection contains a USERGROUPS navigation property.</p>
  
  <p>Users are accessed through <code>/api/Users?$expand=USERGROUPS</code>.</p>
  
  <p>USERGROUPS navigation property contains ID, and I would like to filter by UserGroups.Id by something like:</p>
  
  <p><code>/api/Users?$expand=USERGROUPS&amp;$filter=startswith(USERGROUPS/ID,'a')</code></p>
  
  <p>Ultimately I'd like to be able to filter on a specific group ID value.</p>
  
  <p>Thanks.</p>