Yes there is an option for that within the Employee Details to make sure their rostering notifications e.g. approvals and requests are not sent to them. It will need to be ticked for all employees separately under their own details. To do this please see the steps below:
In regards to the managers, are they currently users on the file like yourself? Meaning they sign in to check or do work within the Payroll System? If they wish to turn of their notifications, they will need to follow the steps in my first response please.
Hope this helps,