Performance of group, Irish, grand initially (3)
I believe the answer is:
gig
'performance' is the definition.
(I've seen this before)
'group irish grand initially' is the wordplay.
'initially' says to take the initial letters.
The initial letters of 'group irish grand' is 'GIG'.
'of' is the link.
(Other definitions for gig that I've seen before include "Live performance; light two-wheeled carriage" , "A one-night musical performance" , "Small horse-drawn carriage" , "Palindromic one-night engagement" , "Horse carriage - performer's single booking" .)