Area range column

I'm looking to replicate something similar to the [arearange](http://www.highcharts.com/demo/arearange) series from Highcharts and was wondering if it could be done with C3. I've gotten close in the past with overlapping series for the upper and lower bounds of the range, but that usually ends up with grid lines and other background styling getting covered in the process. Curious if there was a better way to go about it?