title: Grouped and stacked columns with shared series
body: <p>It's almost like this: <a href="https://www.highcharts.com/demo/column-stacked-and-grouped" rel="nofollow noreferrer">https://www.highcharts.com/demo/column-stacked-and-grouped</a></p>
  
  <p>Except that I want to have John (or any other person) in both stacks. In my case, each person is not either Male or Female, they are part of both.</p>
  
  <p>Here are my categories and series:</p>
  
  <pre><code>categories: [
      'Apples', 'Oranges',
  ],
  
  series: [
      {
          name: 'John',
          data: [1, 9],
          stack: 'Type A',
      },
      {
          name: 'John',
          data: [2, 10],
          stack: 'Type B',
      },
      {
          name: 'Joe',
          data: [3, 11],
          stack: 'Type A',
      },
      {
          name: 'Joe',
          data: [4, 11],
          stack: 'Type B',
      },
      {
          name: 'Jane',
          data: [5, 12],
          stack: 'Type A',
      },
      {
          name: 'Jane',
          data: [6, 13],
          stack: 'Type B',
      },
      {
          name: 'Janet',
          data: [7, 14],
          stack: 'Type A',
      },
      {
          name: 'Janet',
          data: [8, 15],
          stack: 'Type B',
      },
  ],
  </code></pre>
  
  <p>But with this, I currently have all names (Janet, Joe, ...) duplicated in the legend.</p>