Exclusive group includes heads of Labour Education Committee (6)
I believe the answer is:
select
'exclusive' is the definition.
(thesaurus)
'group includes heads of labour education committee' is the wordplay.
'group' becomes 'set' (set is a kind of group**).
'includes' means one lot of letters goes inside another.
'heads of' suggests taking the first letters.
The first letters of 'labour education committee' is 'lec'.
'set' enclosing 'lec' is 'SELECT'.
(Other definitions for select that I've seen before include "Pick among chosen group" , "Choose from the elite?" , "Choose, decide" , "Decide on - first-class" , "Exclusive, admitting only certain people" .)