Area of intellectual activity affected our group (6)
I believe the answer is:
campus
'area of intellectual activity' is the definition.
(eg a university campus)
'affected our group' is the wordplay.
'affected' becomes 'camp' (camp can mean exaggerated or affected).
'our group' becomes 'us'.
'camp'+'us'='CAMPUS'
(Other definitions for campus that I've seen before include "Grounds of university or college" , "university position" , "educational grounds" , "university territory" , "University or college site" .)