Find with less than

[crazybake]

This should be simple:

I have a relationship: classes:className::Students:className...

In the table classes it shows all classes... When I choose a class from a drop down menu, I have a script trigger that gets related record and shows me the students for the class in a new layout.

I have a field that shows current grade from 0-4 (students:current grade).

I tried to create a value list based on this field so that I can have a drop down menu. This will allow me to choose 2.0 for example... I want to constrain the previous find of the related records so that it only shows 2.0 or less in the same layout.

Cannot figure it out... Help