If you use excel I enclosed a little VB Macro Nested loop. It is very small but from it you can do great things with it You need to have the developer add on to do this. You can screen what ever you want out of a spreadsheet. Lean a little vb and do what ever you want done between the Two Ys. You can record as macro changing worksheet and use that macro code as a base to put the loop in
CajunFarmer
For x = 1 To 1000
For y = 1 To 1000
If Trim(Cells(x, 1)) = Trim(Cells(y, 3)) Then Cells(y, 2) = "w"
Next y
Next x
CajunFarmer
For x = 1 To 1000
For y = 1 To 1000
If Trim(Cells(x, 1)) = Trim(Cells(y, 3)) Then Cells(y, 2) = "w"
Next y
Next x