Current group of students (6)
I believe the answer is:
stream
This clue is a triple definition!
'current' is the first definition.
(I know that current can be written as stream)
'group' is the second definition.
(stream is a kind of group)
'of' acts as a link.
'students' is the third definition.
(stream can mean a class of similarly able pupils)
(Other definitions for stream that I've seen before include "Fly" , "Moving water" , "Brook or rivulet" , "Natural body of running water" , "Torrent" .)