Right to be admitted to several clubs (7)
I believe the answer is:
drivers
'clubs' is the definition.
(driver is a kind of club)
'right to be admitted to several' is the wordplay.
'right' becomes 'r' (common abbreviation).
'to be admitted to' is an insertion indicator.
'several' becomes 'divers' (I've seen this before).
'r' going into 'divers' is 'DRIVERS'.
(Other definitions for drivers that I've seen before include "Motorists; clubs" , "Chauffeurs" , "People taking cars" , "Motoring" , "Golf clubs" .)