Vertical gridlines in multi-level category chart Excel 2013

[trpltongue]

Hello all!

I have a 4 level x axis column chart, and I'd like to add vertical gridlines to separate the second level of data. I've tried adding a second axis and associated vertical gridlines, however, the problem is that my charts are linked to dynamic data where the number of sets of data changes depending on which item is selected.

Is there any way to natively add vertical gridlines for multilevel axes, where they only appear at a category break?

I hope the question makes sense, as I cannot post a workbook with the prescribed information.

Thanks,

Russell