How do I assign a value to a pivot table field based on a cell value?

I have a plant name and I want it to be selected based on the plant name I
have on the A1 cell... can I do it?

Plant (All)
Customer Site (Multiple Items)

Sum of Reject Qty Month
Universal Code Jan Feb Grand Total
0000000000 96 434 530
0000002700 17 117 134
0100000000 378 1319 1697
0100000014 3 23 26