title: How to retry on error only inner observable?
body: <p>I have the following sample:</p>
  
  <pre><code>const result = http.get('http://google.com')
  
                 .switchMap(() =&gt; 'http://example.com')
  
                 // This retry should retry only example.com
                 .retryWhen(error =&gt; 
                      (error instanceof Response &amp;&amp; error.status == 429) ?
                       Observable.timeout(5000) : Observable.throw(error))
  
                 // This retry should retry google.com
                 .retryWhen(error =&gt; Observable.timeout(5000))
  </code></pre>
  
  <p>I want to have a retryWhen which will retry only his immediate parent. And then in case of a global error I will retry the whole sequence. Is there an easy way with RxJS 5 ?</p>
  
  <p>UPD: These are just examples. In reality situation is more complex I just need an idea for this.</p>