Let's say you want to build a decentralized discord or slack. If there are two people involved, you could just have the public key of alice encrypting the data that bob sends so that it can be decoded by the alice using her private key. But how would it work if it's a chatroom? Do there need to multiple copies of that data to be stored in the decentralized network? Wouldn't that be redundant? Is there a way to do this without creating multiple copies each encrypted by a the key of each participant in the group chat?