SWI1 - restrict results based on Org structure auth

we have a requirement to restrict SWI1(Workflow Report) output based on who executed the report. For example, A new hire workflow is implemented for the entire organization, and the access to SWI1 is given to different departments admins. If the admin from Dept. A accesses SWI1, he/she should only be able to see new hire process workflow instances initiated by users who belong to Dept. A.

Is there anyway to restrict this? I know this is more of a Security question, posting it here as well Just In Case...

Appreciate your help,

Saurabh