If you create a new Org under a non-Master scope, by setting your scope selection to that non-Master before you create the new scope, it will be accessible from both the non-Master scope you selected and the Master scope when you create it.
So say we have a scope called "Default" that everybody uses and you mainly use the "Master" scope as your default, set your scope to "Default" before you create a new Org. The downside is if you want your staff to be able to create Org's and they don't have access to the "Default" scope...