Restrict users to see specific Grade and Business Unit's person and employment data

Summary

Restrict users to see specific Grade and Business Unit's person and employment data

Content

Hi, 

I have a below requirement to restrict the data for person and employment screen.

1.  only 1 person can see data of  employees of specific Grade  and  Business Unit

2. HR's cannot see  data of Specific Grade of  their own BU 

Can anyone please provide some inputs how to achieve above 2 scenarios.

Thanks 

Praveen