Formula to return unique matches

Hi

I have the following array formula:

PHP Code: 

=INDEX(longextract!$BU$2:INDEX(longextract!$BU:$BU,HideMe!$J$2),SMALL
(IF(longextract!$BS$2:INDEX(longextract!$BS:$BS,HideMe!$J$2)=$A$2,
ROW(longextract!$BS$2:INDEX(longextract!$BS:$BS,HideMe!$J$2))),ROW($A2)-ROW($A$1))-1,0) 


When copied down a column, this gives me all records in longextract!BU where the same row of longextract!BS = A2. Is there a way to alter this formula where it will only return the unique records in BU instead of all of them?

Thank You