Bishop with group (4)
I believe the answer is:
band
'group' is the definition.
(band is a kind of group)
'bishop with' is the wordplay.
'bishop' becomes 'b' (abbreviation used in chess).
'with' becomes 'and' (I've seen this before).
'b'+'and'='BAND'
(Other definitions for band that I've seen before include "A collection of musicians in ring" , "troop" , "Musicians - circle" , "Ring or musical group (4)" , "Outline drawing" .)