title: Override method from class to modify method in children
body: <p><code>ClassA</code> has two children :  <code>ClassB</code> and <code>ClassC</code>.</p>
  
  <p>We need to override a method of <code>ClassA</code> but we will be using <code>ClassB</code> and <code>ClassC</code> (with the modified method).</p>
  
  <p><code>ClassA</code>, <code>ClassB</code> and <code>ClassC</code> are all part of an external library which we can not modify.</p>
  
  <p>Is it possible to get this done without subclassing <code>ClassB</code> and <code>ClassC</code> seperately using the same re-implementation of the method in each subclass?</p>
  
  <p><em>Would the problem be different if <code>ClassB</code> already had a re-implementation of the method that we wanted to ignore?</em></p>