Highcharts line chart with grouped series tooltips - highcharts

Question

I have a line chart that plots multiple datasets where each dataset has two lines associated with it: a reference line and a measured line.
To plot all of these lines, I added individual series for each subset of data, giving the reference line a dashed appearance and the measured line a solid appearance.
The tooltip formatter displays a popover of detail data for a specific point based on the cursor position. It only displays data for one series.
How might I group the series together in such a way that I can display a tooltip for multiple series, but not necessarily all of the series?
Highcharts seems to have an option for shared that displays a tooltip for all of the series that correspond to the cursor's X coordinate, but is there a way to do some sort of grouping? Is there something I can do to the series configuration so that each series renders two lines on the chart but with different appearances?
Not sure if what I'm trying to do is possible with Highcharts. Might need to be a custom chart.

Answer 1

There is no such default functionality in Highcharts, but for now I see two possible workarounds:
slight change in x value:
series: [{
data: [1, 1, 1]
}, {
data: [[0.0001, 2], [1.0002, 2], [2.0002, 2]]
}, {
data: [3, 3, 3]
}, {
data: [[0.0001, 4], [1.0002, 4], [2.0002, 4]]
}]
Live demo: http://jsfiddle.net/BlackLabel/v1uxp3jh/
wrap of the refresh method to exclude some of the unwanted points:
(function(H) {
H.wrap(H.Tooltip.prototype, 'refresh', function(proceed, points) {
points.forEach(function(p, i) {
if (p.series.name === "Series 2") {
points.splice(i, 1);
}
});
proceed.apply(this, Array.prototype.slice.call(arguments, 1));
});
}(Highcharts));
Live demo: http://jsfiddle.net/BlackLabel/qd4mnx8e/
Docs: https://www.highcharts.com/docs/extending-highcharts