Group getting possessive pockets grand in racket (8)
I believe the answer is:
clangour
'racket' is the definition.
(both can mean a loud noise)
'group getting possessive pockets grand' is the wordplay.
'group' becomes 'clan' ().
'getting' says to put letters next to each other.
'possessive' becomes 'our' (possessed by us).
'pockets' means one lot of letters goes inside another.
'grand' becomes 'g' (G is short for grand as in a thousand).
'clan'+'our'='clanour'
'clanour' enclosing 'g' is 'CLANGOUR'.
'in' is the link.
(Other definitions for clangour that I've seen before include "Commotion" , "Loud ringing noise" , "Loud resounding noise" , "Uproar; loud repeated noise" .)