I have bar charts in highcharts. I want to define 3 different bar widths when "plotOptions" is set to grouping false.

With this code:

plotOptions: {
    bar: {
        grouping: false,
        shadow: false,
        borderWidth: 0,
        borderRadius: 0,
        borderRadiusTopRight: '50%',
        borderRadiusTopLeft: '50%',
        color: ''
    },
}

And 'series':

{
    name: 'a',
    data: [30.6, 27.8, 25.8],
    pointPadding: 0.2,
}, {
    name: 'b',
    data: [21.6, 24.8, 22.3],
    pointPadding: 0.28,
},
{
    name: 'c',
    data: [15.6, 18.8, 17.6],
    pointPadding: 0.36,
}

I have this result:

But I want to adjust the width of the 3 bar. For exemple 'a' series 16px 'b' series 8px and 'c' series 3px.

https://jsfiddle.net/u3wvdrzo/