This question is related to: Is it possible to have several ORB objects in the same process?
So, thanks to @BrianKelly I found information about the OR
The ORB will use different connections (and threads) to different servers every time - always. Receiving answers and incomming calls are also handled in different threads (if useful and/or needed).
I think you try try to solve things, that the ORB already has solved for you. It's a middleware, don't scare about threading and stuff. It's already done by CORBA experts.