title: How do I navigate different child components within a mat-tab? (not in primary outlet)
body: <p>My AppComponent contains a sidenav and a router-outlet. Each menu item allows me to navigate to a different feature.
  Each <em>feature module</em> has four main components: </p>
  
  <ul>
  <li>component 1: list => url /feature/list</li>
  <li>component 2: details => url /feature/details/123</li>
  <li>component 3: edit => url /feature/edit/123</li>
  <li>component 4: add => url /feature/add</li>
  </ul>
  
  <p>When I click a feature from the sidenav I'm presented with the features' list-component by default. </p>
  
  <p>On each features' list-component I'm using navigation buttons to navigate to the corresponding <strong>details</strong>, <strong>edit</strong> and <strong>add</strong> components via URL like this: <code>this.router.navigateByUrl('/feature/details/123')</code>.</p>
  
  <p>One of my features has a <code>mat-tab-group</code> in its 'details component'. When I navigate to this component (e.g. <code>/feature/details/123</code>) I would also like to be able to click on some tab and see a list-component. But to be clear, I want this component visible within the tab, not in the primary outlet.
  This list should show a table with some data from id:123. Also this embeded list-component should have different buttons to allow me to navigate to its corresponding details, edit and add components.</p>
  
  <p>I've tried to implement auxiliary routes, and named router-outlets, but I must be doing something wrong because I just can't get this to work. I may not understand the innerworkings properly.</p>
  
  <p>Could someone please explain how I should tackle this? If it is even possible at all?</p>