title: How do I navigate to a sibling route?
body: <p>Let's presume I got this router config</p>
  
  <pre><code>export const EmployeeRoutes = [
     { path: 'sales', component: SalesComponent },
     { path: 'contacts', component: ContactsComponent }
  ];
  </code></pre>
  
  <p>and have navigated to the <code>SalesComponent</code> via this URL</p>
  
  <pre><code>/department/7/employees/45/sales
  </code></pre>
  
  <p>Now I'd like to go to <code>contacts</code>, but as I don't have all the parameters for an absolute route (e.g. the department ID, <code>7</code> in the above example) I'd prefer to get there using a relative link, e.g.</p>
  
  <pre><code>[routerLink]="['../contacts']"
  </code></pre>
  
  <p>or </p>
  
  <pre><code>this.router.navigate('../contacts')
  </code></pre>
  
  <p>which unfortunately doesn't work. There may be an obvious solution but I'm not seeing it. Can anyone help out here please? </p>