Towny Chat Channels Help

I want to setup my config to make it a more fluid experience. How do I make it so when someone joins a chat channel, they leave the old channel. For example: Someone joins their town chat from their nation chat, but they leave the nation chat automatically. Also, I would not want this to effect global chat, so everyone can see global chat.

Also, on another note, I'd like to give an error message when someone tries to join a chat that they're already in. Currently, if someone types /tc to enter town chat, and they type it again, they join back into global/general chat. Is there any way to make the second /tc command return an error such as "You are already in town chat!" I've seen both of these done on several Towny servers, and I'd love some help.

Thank you very much for any help!

 

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