If you're registering multiple destinations and they are all subscribing for a particular event on an event bus, all of those destination will notified when that event is published. This is the intended way the Otto bus works. It follows the publish / subscribe pattern.
It's important to note that it's not because you're registered to an event bus that you will get all of the event being posted to that bus. You need to also subscribe for that event.
Alright for you use case, do you really need to be registered to that specific bus? Seems like you don't want to be notified of specific events being used within that library. Why don't you just create a second Bus instance? You could then use it to communicate within your app only without conflicting with your library communication. This would allow you to be subscribed to the same events that the library uses but only your app would be registered to that app. That would create the separation that I think you're looking fore. So in conclusion you'd have original bus for the library communication and a second bus for your app communication.
Maybe I'm missing what you're trying to do here.