Flexible Performance Management: Adding additional Role

Hi,

I have a requirement where an additional role is required, thus 3 roles are required: an employee, a supervisor and the manager. Now the manager will be only updating the document at the final stages with a comment so he will not be participating in the appraisal process itself..Thus i'm confused on how to tackle this requirement shall i add him as a part appraisal, if so then the Part appraisal column is required and it gets complicated in status flow..

Any Recommendations..

Thanks in Advance

A. Salah