You absolutely need proper security.  Set up security groups by employee positions. I like to use the menu numbers with an extra zero so that I can see the main access that group has.  For example 40 for AP clerk, 60 for Project Managers, 20 for Controller.   Then you can add subgroups to grant access to only a sub menu if needed.  For example 55 for daily payroll.  Then you have to set security on each level using the F7 button.   To access any sub-menu the user group must also have access to the main group.  So group 55 would need access to menu 5 for payroll and menu 5-5-1 for daily payroll, but NOT have access to any other menus in payroll unless appropriate.  In order to block groups, you have to have at least one group that does have access, such as the Full Payroll group or controller group.   You can check security settings at menu 13-7, report #22.  Or use report #23 to check what menus a specific group or user name has.  If you need help analyzing your security, Wright Office Solutions has a program that will do that for you.  

https://wrightoffice.com/s100-contractor-security-analysis/

We have it set up like you do.  One Admin who knows everything and then access according to position.