Starring roles for ushers (5)
I believe the answer is:
leads
I believe this is a double definition.
'starring roles' is the first definition.
(I've seen this in another clue)
'ushers' is the second definition.
(I know this)
'for' is the link.
(Other definitions for leads that I've seen before include "Clues" , "Actors who play principle roles" , "Guides from the front" , "Actors who play principal roles" , "What Prime Minister does" .)