Small group of musicians, not all illustrious (4)
I believe the answer is:
trio
'small group' is the definition.
(group of three people)
'musicians not all illustrious' is the wordplay.
'TRIO' is hidden in amongst the letters.
However, I am uncertain how this is indicated.
'of' is the link.
Can you help me to learn more?
(Other definitions for trio that I've seen before include "father, spirit and son" , "Band of three" , "Ensemble musical piece, eg Beethoven's 'Archduke'" , "Chamber group" , "Riot (anag)" .)