Control Workflow Report output using Structural Authorization

Is it possible to control output of Workflow Reports using Structural Authorizatins. E.g. Workflow Admins having access to tcode SWi2_FREQ will be able to see project wide data, but i want to restrict the workflow admins at department level from seeing workflow data for other departments. is that possible using Structural authorizations or any other mechanism?

My understanding is that Structural authorizations pretty much control PA/PD, and not other modules. I did a quick test,

1) Created a org structure

2) Created employees, users, and set up structural authorizations

Now when users are granted authorization to PA20, they are restricted to what they should be seeing, but when they are granted authorization for workflow admin reports, structural authorization don't seem to work, they are able to see data for workflow triggered for other departments as well. Is that the standard behavior or i am missing something. I don't have enough experience with Structural auth.

I will appreciate any guidance on this matter.

Thanks,

Saurabh