Exclude Databases option

Hi
I scheduled a backup job using the EXCLUDE OPTION to set aside thos databases i don't need to regularly backup.... Job is running well without any problems

Our SQL Server manages hundreds of databases some of which don't need to be backed up (demo databases) and therefore are excluded. If a DB is no longer required it is manually excluded from the respective backup jobs.

Question: How does SQL Backup keep track of the Databases that are backed up?. Is this list stored at some location?
I'm looking for a way to automatically exclude a database when it's no longer required to be backed up and update the job accordingly. Deleting the datase obviously would solve it but not a good alternative

Thanks in advanced