Group of people fixed part of match (3)
I believe the answer is:
set
I believe this clue is a triple definition!
'group of people' is the first definition.
(eg a social set)
'fixed' is the second definition.
(both can mean decided or determined)
'part of match' is the third definition.
(tennis term)
(Other definitions for set that I've seen before include "Prepared" , "decline" , "Become fixed or solid" , "Class" , "Fix in place; similar group" .)