Ignore values in a particular row for Grand Total
 

Hi, i have a pivot table which is somthing like this:

a b c d e f
-------------------
x |1 0 1 2 1 0
y | 2 0 2 1 2 0
z | 1 1 0 1 0 1
--------------------
total 4 1 3 4 3 1

My problem is that i would like the total at the bottom to be the sum of
rows x and y, but not z. If i remove row z from the pivot then the totals are
correct however columns b & f disappear. Does anyone know of a way that i can
either:

1 - tell the pivot table to ignore row z in the total, or
2 - remove row z but keep colums b & f in the table?

thanks in advance