Pivot tables - multiple selections for same fields

Hi

I have a monthly sales report that shows YTD 2019 and Totals for 2018/2017/2016 by default; i.e. months 1 to 12 are all selected. I'd like to insert another column that shows YTD 2018 but keep the Totals in place.

Obviously if you change the months selected then all of the previous years revert to showing YTD.

Could anyone help me in how to do this please?