Role(s) for a backup operator?

Hello,

I would like to utilize the existing role and privilege sets in Enterprise Manager Cloud Control 12c to create custom roles.  What I'm finding difficult, however, is defining a specific role (or roles) for an EM user to be given for a specific purpose.  This user's only responsibility would be to manage backup jobs.  The user should be able to manage and monitor submitted job runs that the user has created in the Jobs Library.

Has anyone come across a good way to do this?  Obviously, an Administrator or comparable user could do this (as I have been doing in 11g); but I would like to isolate an EM user for his or her specific job function.