What you’re reading about intelligence quotient in group (6)
I believe the answer is:
clique
'in group' is the definition.
(I've seen this in another clue)
'what you're reading about intelligence quotient' is the wordplay.
'what you're reading' becomes 'clue' (I've seen this in another clue).
'about' indicates putting letters inside.
'intelligence quotient' becomes 'IQ' (synonyms).
'clue' going around 'iq' is 'CLIQUE'.
(Other definitions for clique that I've seen before include "Small exclusive groups of people." , "Inner circle" , "A small exclusive group" , "set" , "Small close-knit group" .)