title: Retrofit & RxJava multiple requests complete
body: <p>I need to do:</p>
  
  <ol>
  <li>Request 2 lists of news from different websites</li>
  <li>Combine results from requests</li>
  <li>Sort items by date</li>
  <li>Get 10 newest news</li>
  <li>Save them</li>
  <li>Show complete message</li>
  </ol>
  
  <p>For example, I have this two observables:</p>
  
  <pre><code>Observable&lt;RegionalNews&gt; regionalNews;
  Observable&lt;NationalNews&gt; nationalNews;
  
  public interface NewsNationalService {
    @GET("news/national")
    Observable&lt;News&gt; getNationalNews();
  }
  
  public interface NewsRegionalService {
    @GET("news/regional")
    Observable&lt;News&gt; getRegionalNews();
  }
  </code></pre>