I'm not familiar with how most of the main chatbots do this, but the one I'm most familiar with is Gemini and I don't believe it has that.
My original message probably didn't do justice to the bigger aspect to this "integration". For example, I envision giving these chatbot services a common API (implemented by the different chatbot companies).
Within this API, for example, it would be possible for me to post the conversation, then someone else could just pickup with that conversation and start asking additional questions about the same topics of that conversation. It would essentially turn these conversations into more of a "graph" representation than a more linear data structure like a list. Also it would be possible to "pickup" a conversation from one chatbot and continue it (by someone else maybe) on a different chatbot.