Second and Multiple rows of Grand Total in pivot chart

Hello All,

I would like to add to the values field of a pivot table, a summarized line of other values, in order to have a second bottom row with the sum of these values as a second row of grand total(and having for instance the primary values associated with each row and each column as a normal pivot chart, as long as the first row of grand total).
Is there any way to do it in excel, or should I work these values in a power pivot environment ? in this second case, would you able to address me to which kind of DAX Formula I should use?

Thanks in advance