No no.
In the example, B do not want to send Voice A.
Then B just off the local microphone by clicking Stop Mic.
Understand?
Hypothetical example:
When you are with someone on the phone, and at some point do not want that someone listen to your hambiente sound, you mute the microphone of your phone without disconnecting the call. After you power cycling your microphone and continues the conversation. Understand?
What I want to do is exactly that, the video chat.
Place the mute function (enable or disable) the local microphone, without shutting down the connection to the other.