Whenever I take my laptop away from my desk (to type on the couch), OSX goes crazy letting me know that my Apple keyboard is connected, now disconnected, now connected, now disconnected... The message appears in an obtrusive grey box right in the middle of the screen. I never want to see that box again. Simply disabling bluetooth is not an option.
If you use the bluetooth menu item, disconnect from any devices that you don't want to show the message.
You could also automate that UI control with Automator. Open that and then make an automation action that uses the "Watch Me Do" tool to record the things you select.
That way you could assign a keyboard shortcut to have both devices disconnect and another to reconnect them when you wish.
Maybe someone else knows how to kneecap the messages, but this would work with what I know.