Just like we have a plugin for grouped xAxis (commonly known as grouped Categories), it would be good if we have some something similar for grouped yAxis
Paweł Fus commented
Regarding labels-translation, it's cased by compatibility with old version of Highcharts, required is to set `labels.x` option. And first category isn't rendered because we need to set strictly yAxis to start from 0 (yAxis.min) to display properly categories.
Still, there is small issue with offset for gridlines in categories, though.
Seems like Black Label's Grouped Categories plugin does a decent job here, though there are some alignment issues: http://jsfiddle.net/highcharts/6ekvghr8/