question about the authorization

Hi experts,

In my company there have two boys in charged of the basis module ...

They are in charging of the different user's management. one is in charging of the factory user, another one is in charging of the office user.

But now i have a question which is how to prevent basis A can modify office user ???

My sap system is SAP 4.7 with oracle 9i

thanks.

Joejs Arugrg