Custom multi-level label on X-Axis

Hello all,

I was wondering if there was a way to edit a chart's Series formula to get multi-level labels on the X axis.

For example, the formula:

=SERIES('Charts'!$A$7,{"USA","Italy"},('Charts'!$F$7,'Charts'!$H$7),1)

Will show two labels, USA and Italy

My question is if there's a way to use {"USA","Italy"} for multi-level labelling, so that it would show something like:

USA - Population ; GDP
Italy - Population ; GDP.

I hope that makes sense? Big thanks in advance!