How to generate data in $.ajax success so it can be passed to Deferred .done() ?

How to generate data in $.ajax success so it can be passed to Deferred .done() ?

Hypothetical situation:
I want to poll 5 newssites, where each news sites returns a differently builded JSON-response.

I use 1 object per website.

So for example, in CNN.js I have a method
grabNews which is a $.ajax() request.

In its success method, I check the JSON response ( data ) and I want to grab only the information that I'm interested in ( # of articles from today ).

I have the same method in my CNBC.js

In another more generic JS file, I have an object named objNewssite which can contain either my CNN or my CNBC object.
Here I want to do the following:

  1. objNewssite.grabNews().done(
  2.       function(.....){
  3.             console.log(numberOfArticlesFromToday);
  4.       }
  5. );

How should I do this?
How do I process custom data in success to make it more generic so I can later use the more generic version in my chaining of the deferreds ?