turn based voicechat

In a voice chat with several people it's not uncommon to be unable to hear what everyone is saying because everyone is talking at the same time. I think this with be a very useful feature that could be implemented with push-to-talk. My idea is that only one person can speak at a time and the order in which people will speak will be determined by the moment they pressed the key they have assigned for talking, it could also come in handy if we could also set a limit for each speaker's turn.