Indulge group with lettuce first (6)
I believe the answer is:
cosset
'indulge' is the definition.
(I know that indulge can be written as cosset)
'group with lettuce first' is the wordplay.
'group with' becomes 'set' (both can mean a collection. I am not sure about the 'with' bit.).
'lettuce' becomes 'cos' (cos lettuce is a kind of lettuce).
'first' is a charade indicator (letters next to each other).
'set' put after 'cos' is 'COSSET'.
Can you help me to learn more?
(Other definitions for cosset that I've seen before include "Pamper, coddle (6)" , "Protect overindulgently" , "Care for overindulgently" , "Nanny" , "Overindulge" .)