This is what I am trying to do and would love someone to show me the correct formula... I have been banging my head against the wall trying to figure it out..

Column B contains the persons last name, Column I contains the address.

I want to Excel to look for duplicates within Column B and within Column I (separately within each column) then ONLY flag the cells red in shaded color if 1) the cell is a duplicate within itself in column I AND it also has the same last name showing in Column B.

Is this clear??

your help would be greatly appreciated...