Are you talking about forcing a login after each transaction, or forcing the Cash Drawer to be closed before transaction completes?
Forcing Login is a storewide setting, although it would be possible to create an add-in that would let you do this based on current cashier.
"Wait for Drawer close" is set up in Register Properties and is global for the drawer. If you added a second drawer, you could set one up to wait for close, and the other not to wait. Then assign cashiers to drawer 1 or drawer 2 based on their trust level.
Generally, you want to enforce the same rules for everyone - makes it easier to train if everyone is working with the same rules.