Authorization control on Project/WBS

Hello Experts,

I have an issue on authorization control project and WBS creation and I seek your guidelines into it.

We have authorization object

These objects control authorization as per 'Person Responsible' field in our project structure. This is a unique field for project and unique for all WBS elements separately.(Each WBS has a person responsible field of its own) (t-code CJ20N)

We have two departments A & B.

A will create the project and B will create the WBS under it. And department B are having 5/6 users to create WBS elements.

Now, I want to know how this matrix should be set up so that only department A users could create the project and Department B users could only create the WBS for this project.

JUST TO ADD (another view): Can we have some Z-authorization objects which will work in conjunction with the above two authorization object to control the project and WBS creation. Actually, I believe the above to std. objects will work in conjunction with 'Person Responsible' field in project hierarchy. I am just thinking that if department A has 'Z-A' authorization object he/she can create project and if department B has Z-B authorization object in his roles he can create WBS elements.

Looking forward for you suggestions on it.

Thanks for the help.

With Regards

Saurabh