Criteria within FILTER for UNIQUE results based on a certain range.

Here is my current formula:

=FILTER(Grades!A:A,(Grades!D:D>=80)*(Grades!B:B=6)*(LEFT(Grades!F:F)="S")*(Grades!G:G<>"08320005"))

This works wonderfully to pull out the information that I need with one potential issue. It will duplicate a result from the same course in different terms. The course numbers are in Grades!G:G, and the term ID's are in Grades!F:F. What criteria can I add to this FILTER that would yield results only one time if a course number in Grades!G:G is repeatedly matching the other criteria?

I have used UNIQUE for this when I need the result of the FILTER to be UNIQUE, but I am not having luck with making a criteria look for uniques.