Social group of chaps ahead of generation (6)
I believe the answer is:
menage
'social group' is the definition.
(menage is a kind of social group)
'chaps ahead of generation' is the wordplay.
'chaps' becomes 'men' (chap means a man).
'ahead of' means one lot of letters go next to another (some letters go in front of others).
'generation' becomes 'age' (I've seen this in another clue).
'men'+'age'='MENAGE'
'of' is the link.
(Other definitions for menage that I've seen before include "Social unit living together" , "Persons of household" , "family group" , "live together" , "a household, may be naughtily a trois" .)