Hello Conrad,
1) Using the target group you can indeed have your transports going to any other system/client you want.
2) That's where the trick is... customizing orders could not be linked to a transport layer through a package as customizing objects do not belong to any package.
But it is possible to define a standard (aka default) transport layer for a system (called ZCUS in my example).
You then need to create specific layer for SAP object and all your packages (dev. class).
So you'll have layers for all packages and the rest (customizing) will follow the route defined for the standard transport layer.
You can push the logic a little bit further as it is even possible to define a standard transport layer for specific client in the system.
Best regards
