Most employees have to check (4)
I believe the answer is:
stem
'check' is the definition.
(both can mean to control or stop)
'most employees have' is the wordplay.
'have' indicates the answer is hidden within the clue.
'STEM' can be found hidden inside 'most employees'.
'to' is the link.
(Other definitions for stem that I've seen before include "Basic skiing turn" , "Axis" , "Peduncle" , "section of pipe" , "Stop the flow of, check" .)