[Solved]-highcharts groups of stacked columns-Highcharts

Okay, to connect series use linkedTo for series. To set stacking, use stacking:'normal' and for series use stack. And here is a result: http://jsfiddle.net/TfvGp/50/

About tooltip, there's no simple solution for it. In Highcharts you can show or all series in tooltip, or just one. You can't choose two series for it. The best solution will be to loop over all series in tooltip.formatter and display series values only for the same stack as hovered point, see docs. Happy coding ;)