Beginning to expose group (6)
I believe the answer is:
outset
'beginning' is the definition.
('outset' can be a synonym of 'beginning')
'expose group' is the wordplay.
'expose' becomes 'out' (outing is a kind of exposing).
'group' becomes 'set' (set is a kind of group**).
'out'+'set'='OUTSET'
'to' is the link.
(Other definitions for outset that I've seen before include "Opening stage" , "Fruit" , "debut?" , "Beginning, start" , "Inception" .)