Hi, I'd like to help you with your question.
No, hallucinations such as you are describing are only one way. The hallucinations are not heard or even seen by other people. The only way someone else would know is if the person having the hallucination told them about it.
But if you mean a person hearing voices has more than one voice they hear, yes, that does happen. These types of hallucinations can be very complex. People with hallucinations can have a multitude of voices that they hear. They often hear people talking about them. It can be groups of two or a large group of people.
There were biomedical studies done recently that indicate people who hear voices are sometimes talking to themselves without realizing it. They were using their voice boxes to make the noise very quietly but did not realize it.
I hope this helps you,Kate
Voices are usually something the person themselves hear and they do not respond to outside stimuli. They are a manifestation of the person's own thoughts and cannot be treated as a separate entity that responds to other people.