In a group, we are nice (5)
I believe the answer is:
sweet
'nice' is the definition.
(both can mean agreeable or pleasant)
'in a group we' is the wordplay.
I cannot quite see how this works, but
'we' is present in the answer.
'group' could be 'set' (both can mean a collection) and 'set' is present in the remaining letters.
This accounts for all the letters.
This explanation may well be incorrect...
'are' is the link.
Can you help me to learn more?
(Other definitions for sweet that I've seen before include "S [SWEET] , basically" , "It is agreeable" , "Humbug!" , "Sugary - but might be tart!" , "delightful" .)