Highcharts - Combo chart grouping but not disaggregating

Question

I'm wanting to create a combo line/column chart where the line points are discreetly presented (1 for each day) and then have columns with other values for a given date range (say, by month), and have the line points show in that month. Is this possible in Highcharts?

I'm guessing I'd need to create categories for the X axes (months) but am unsure how to retain the day-level detail in my line series as it seems like a 1:1 mapping?.

In the example below, is it possible to "group" the last line points between say Sept and Nov? Attempt at adding and grouping an additional (test) series to stock example:

{
        name: 'Foo',
            type: 'line',
        data: [20, 34.8, 39.3, 41.4, 47.0, 48.3, 59.0, 59.6, 52.4, 65.2, 59.3, 51.2, 90, 40, 22, 10, 12, 30, 36, 50],
        pointPadding: 0.2,
        grouping: true

    },

https://jsfiddle.net/023a1ypj/

Any tips appreciated