So, normally these "Home" Threads are private and so also n…

So, normally these "Home" Threads are private and so also not written to the blockchain, right?
Now, imagine that I would like to have "group chat" between me and let's say a possible "buyer" of something I offer this person.
As we (somehow), in that "group chat", setup a "contract" we would love maybe have the option to write that private Home chat to the blockchain.
I am expressing myself clear enough? What do you say about this idea?