Once an app is published to a stream, you can not edit the script. What you might want to do is create custom roles and custom rules that allow users with those roles to publish only to certain streams.
I also try to never edit the seeded rules. I just disable them. I chose to create developer roles using custom properties at first and then moved on to AD groups.
Example rule below. This rule allows our developer admins to publish to any stream with a name that begins with UAT.
Rule Name: PublishStreamUAT
Resource Filter: Stream_*
Action: Publish, Update
Condition ((resource.name like "UAT*") and (user.group="QlikView Administrators")