is it possible to nest/group labels in chart axes? For example our chart horizontal axis shows the year and the month. The result looks like this:

What I want to be able to do is group them all together by year, so similar to:

01   02   03   04   05   06     01   02   03   04   05   06

                2016                                    2017

Is this possible as I can't see any options to be able to do this.