Small group, owing to time (4)
I believe the answer is:
duet
'small group' is the definition.
'owing to time' is the wordplay.
'owing' becomes 'due' (similar in meaning).
'to time' becomes 't' (abbreviation).
'due'+'t'='DUET'
(Other definitions for duet that I've seen before include "Composition for two performers" , "Work for a couple" , "Two singers performing together" , "Paired performance" , "Performance by two" .)