The point is I would like to keep the behaviour of a stack chart, especially the fact that when you click on the legend to hide/show data, the percentages are automatically updated (which is really nice and useful).
It is possible to do it by catching the legendItemClick event and then recalculating the data accordingly, but this is quite painful (compared to using a stack chart).
Thank you for your comment and sorry for the lack of information.
Actually I first posted a question on stackoverflow about this, you can find it here : http://stackoverflow.com/questions/22534359/highcharts-grouped-columns-with-percentages
The point is I would like to keep the behaviour of a stack chart, especially the fact that when you click on the legend to hide/show data, the percentages are automatically updated (which is really nice and useful).
It is possible to do it by catching the legendItemClick event and then recalculating the data accordingly, but this is quite painful (compared to using a stack chart).