Push a key to temporarily lower the volume of other people in a call

Streamers typically are in a voice call with other people while live, and sometime will want to talk to their chat for a moment without being heard on other streams. But with the other people talking in the call over them, it is hard to understand what they are saying, especially with a big group!

There should be a way to temporarily lower the volume of other callers while simultaneously muting yourself to the call so that chat can differentiate which voice to focus on.