Put more than one companion in the same room. Each keeps their own personality and memory of you, and they respond to what the others say.
A group chat changes the dynamic. Companions disagree with each other, tease each other, and take sides — which turns a conversation into something closer to a scene. It is also a fast way to see how differently two characters are written.
You can create as many groups as you like and move companions in and out of them.