In a past attempt at something like this… I actually created a new message type, and modified the bot framework to grab those message types. Because it was a new message type I was able to keep it from being displayed to end user, but the bot would receive it.
I’ve also wondered about bots… If official and a way to register a bot… maybe could actually subscribe to an event stream for that bot. Then message responses like this could actually just be sent to the bot over it’s event stream.