Stick to personnel (5)
I believe the answer is:
I believe this clue is a double definition.
'stick' is the first definition.
(I know that staff is a type of stick)
'personnel' is the second definition.
(staff is a kind of personnel)
'to' acts as a link.
(Other definitions for staff that I've seen before include "Man" , "Employees; spindle in watch" , "teachers possibly used" , "Group employed in services etc" , "something orchestra member may look at" .)