Networker "Password" for encryption (not user passwords (such as admin))

Is it possible to set passwords for server initiated backup job. With different jobs having different passwords. A restore will need the password associated with that server/job.

I am aware of passwords within the client initiated backups, which I interpret as a mechanism for the backup to be encrypted.

The reason we would want to do this is sometimes we get requests from data providers to delete  backups that contain data we are no longer allowed to have. This is often near impossible to delete from tape without deleting other servers backups. Also what may need to be deleted is a single record in a database, and losing backups to the request is a mission critical issues

Data Providers will accept our legal dept having that password and not releasing it without informing them, and having a procedure that give the data provider assurance that "data subject to deletion" will not be recovered.

I know most of you will be saying "this is crazy, you must keep backups for assurance on integrity and availability", you are of course correct but when you have to dance to the tune the data provider specifies, you dance to that tune.