I have a table with 5 columns: The first column (A) lists parts, the second (B) lists countries, the 3rd (C) is a concatenation of the first 2 columns, and the 4th (D) is a concatenation of the same list of parts but other related countries. There are many more countries in column D than in column C, so most of the values in column C are duplicated multiple times. The values in column D do not duplicate. Column E indicates if there is a match between columns C & D.