Hello Brayan,
You say, you when you want to Assign a Bussiness Object to the Process, you can see all the bussiness objects from all process you have?
There is no way to view only the process asigned to the process from the BPM, the only way to see is going to the bpmn, clic on Edit Process Parameters and you can find all the BO's assigned to that process.
Regards.