transport to multiple systems using one package

My customer has one development instance that services two test and production landscapes for seperate geographical regions. This is a new installation and they are developing using packages. They currently belive that they can transport the objects from those packages to each landscape via the same package, transport layer and transport route. I'm contending that that is not possible and that they will have to create a seperate package with the same objects for each landscape if they want to transport to both. I'm a bit inexperienced at this and could use any advice available. Is it possible to setup STMS transport routes to transport to two seperate environments from the same transport layer?

Regards.