title: How to create multiple stackNavigator?
body: <p>Hello I'm trying to create:</p>
  
  <ul>
  <li>A top Bar for all screen </li>
  <li>a bottom bar for only 4 screen</li>
  </ul>
  
  <p>So I have 2 screens -> Home screen and connection screen (without any top or bottom bar)</p>
  
  <p>Then I have my 6 screen A B C D E F</p>
  
  <p>I want a top bar on each and a bottom on A B C F</p>
  
  <pre><code>const TabRouter = createBottomTabNavigator(
  {
    HomeAfterLoginScreen: { screen: A },
    ShowListAlertScreen: { screen: B },
    ShowListProfessionScreen: { screen: C },
    MyAccountScreen: { screen: F }
  },
  {
    tabBarPosition: "bottom",
    tabBarOptions: {
      style: { backgroundColor: "#50bcb8" },
      showIcon: true,
      showLabel: true,
      gesturesEnabled: true,
      indicatorStyle: { borderBottomWidth: 3, borderBottomColor: Style.color },
      inactiveTintColor: "#fff",
      activeTintColor: "#fff",
      tabStyle: { justifyContent: "center", alignItems: "center" }
    }
  });
  
  const Router = createStackNavigator({
    // If I add A B C F here i loose my bottombar
    D : {
      screen : D, 
      navigationOptions: {(nav option ..)}
    },
    E : {
      screen : E, 
      navigationOptions: {(nav option ..)}
    },
    Home: {
      screen: HomeScreen,
      navigationOptions: {(nav option ..)}
    },
    App: {
      screen: TabRouter,
      navigationOptions: {
        visible: false,
        header: null
      }
    },
    ConnexionScreen: {
      screen: ConnexionScreen,
      navigationOptions: {(nav option ..)}
    },
  });
  
  export default Router;
  </code></pre>
  
  <p>There is a sample of my router.js </p>
  
  <p>With this configuration I have bottom bar but I don't have my top bar. Any advice?</p>
  
  <p>this is my screen A and i want a top bar on it. but if if add this screen on creatstack navigator i loose my bottom bar.
  <a href="https://i.stack.imgur.com/CEKRx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CEKRx.png" alt="enter image description here"></a></p>