title: ag-grid: use more than one group cell rendering in a single row
body: <p>Within the data, I am trying to use the group cell renderer to display sub-table data within a row. it works perfectly. When I try to use the group cell renderer on another column in the same row, it doesn't work because the group key honors whichever reference is read last by the compiler. Based on that, is there any way that I can override the group cell renderers parameters to allow for more than one in a single row?</p>
  
  <pre><code>let columnDefs = [
    {headerName: 'Company', field: 'company'},
    {headerName: 'Job', field: 'job'},
    {headerName: 'Time Wasted', field: 'timeWasted'},
    {headerName: "People",
      children: [
    {headerName: "", cellRenderer: 'group'},
    {headerName: "Athlete", field: "athlete"},
    {headerName: "Year", field: "year"},
    {headerName: "Country", field: "country"},
      ]
    },
    {
      headerName: "Details",
      children: [
        {headerName: "", cellRenderer: 'group'},
        {headerName: "Time", field: "time"},
        {headerName: "Speed", field: "speed"},
        {headerName: "Distance", field: "distance"}
      ]
    }
  ];
  
  //options for chart configuration
  this.options = {
    columnDefs: columnDefs,
    enableColResize: true,
    enableSorting: true,
    getNodeChildDetails: getNodeChildDetails,
    enableFilter: true,
    rowSelection: 'multiple'
  };
  
  this.data = [
    { company: 'BMI',
      job: 'developer',
      timeWasted: '15 days',
      group: 'People',
      participants: [
        {athlete: 'Jimmy Blue', year: '2008', country: 'United States'},
        {athlete: 'Jack Brown', year: '2009', country: 'China'},
        {athlete: 'Jeff White', year: '2010', country: 'India'}
      ],
      group: 'Details',
      stuff: [
        {time: '14:04', speed: '11', distance: '1.2'},
        {time: '16:03 ', speed: '12', distance: '1.25'},
        {time: '17:00', speed: '12', distance: '.99'}
      ]
    }
  
  ];
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/BVPzz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BVPzz.png" alt="enter image description here"></a></p>