Add persons to conversation without creating a named conversation

[BiglifeMatt]

Unsure if this already exists somehow and I do not know how to do it:

I feel like it would be convenient to type names in the search/lookup box and automatically create a small group conversation without having to create a named instance of a conversation and then adding members to it. It would even be nice to add a person to a one-on-one conversation after it has started.

[nickvergessen]

It would even be nice to add a person to a one-on-one conversation after it has started.

We had this in the past and it was very confusing that they "lost" their one-to-one chat and also it leaking all their past history.