Stop daughter joining group (4)
I believe the answer is:
band
'group' is the definition.
(I've seen this before)
'stop daughter joining' is the wordplay.
'stop' becomes 'ban' (I've seen this before).
'daughter' becomes 'd'.
'joining' says to put letters next to each other.
'ban'+'d'='BAND'
(Other definitions for band that I've seen before include "Belt; group of musicians" , "Group; frequency range" , "See 23" , "Pop group, perhaps" , "Players" .)