That command will already do what you want. do you see it not doing that ?
Actually, the deletion was failing on certain packages with dependencies, and I now think I know why.
By default, when a user creates a job, BLAdmins is granted full permissions to the job.
It appears that some users took it upon themselves to remove BLAdmins from some jobs, which in turn caused the package delete to fail since BLAdmins no longer had permission to the dependencies.
I should have taken a much closer look before posting.
So sorry for taking your time.