Idk if this is implemented on Java yet, but I know for a fact that it isn't on Bedrock, and I would like to change that. This would be so useful during skywars or eggwars, when you need to talk to your team privately when you don't have a microphone, or if you're going into a teams match without a teammate (or for the new mega skywars, wink wink). You could toggle the default to be either, and add an @ or a # to switch from the default to something else. For example, you could have your game set up where the default is global chat, an @ before the message activates team chat, and # before the message activates party chat. You could have custom binds set up as well, and all of this would be perfect for the server as a whole.