Conditional Formatting and Duplicate Values

I am sorting through addresses and need to find duplicates.

The data are listed as similar to the following:
Name Address 1
Ben John Doe 123 Lazy Lane, New York, Ny
Brian Doe Family, 123 Lazy Ln, New York, New York

The main problem is there are about 100 total "Names" (rows) with each person reporting 15 different addresses (in different columns) for mailing. Since the data was done from a survey into Google Doc, each person formatted their addresses in a different manner, making it difficult to sift through and see if there are duplicates.

I was wondering if there was a way to highlight all the potential duplicate addresses in the worksheet to better narrow my search for duplicates, so that I do not have to go through the 1000+ addresses manually.

If addresses are in B2:B7, this will return true/false as to whether there are repeated numbers. Enter in the conditional formatting box with Ctrl+Shift+Enter.

=(SUMPRODUCT(--(LEFT($B$2:$B$7,3)=LEFT(B2,FIND(" ",B2)-1))))>0