it might be faster just to sort the excel data, split it into two sheets, one
with the 3 postal codes and one withtout, and do two different merges.

"ADJS" wrote:

Hi
Can anyone advise me how to create an IF command in an Excel data source
which will enable any letter created in word to include a sentence if the
Postcode entered is included in the 'IF' cell.

To clarify I need to input a sentence into a word document which has data
entered via mail merge but only if the postode is equal to any one of three
codes.