Stays in my group (6)
I believe the answer is:
corset
'stays' is the definition.
('corset' can be a synonym of 'stays')
'my group' is the wordplay.
'my' becomes 'cor' (I've seen this in other clues).
'group' becomes 'set' (set is a kind of group).
'cor'+'set'='CORSET'
'in' is the link.
(Other definitions for corset that I've seen before include "Shaping undergarment" , "Tight-fitting bodice" , "Stiff supportive undergarment" , "female garment!" , "Item of underwear" .)