Hello
Please Discuss with You Business process Owners and Prepare authorization Matrix in which you can decide each person's privileges and authorization need to give for carrying out business transactions. Also you need to create Different Roles with help of Basis and Security Consultant,design Roles such way that you can assign those to Each persons profile according to his actual role in business ,privileges and authorization .
Note:Role-->Have set of Authorization Object assigned
Please take help of Basis and security Consultant
Br
Rakesh