AirPlay or Bluetooth Device - Does one like this exist?

I am looking for a speaker or speaker dock that would help me accomplished this 'flow'

Listening to a podcast with DownCast while out of the house > walk into the house > have a speaker that is always turned on pickup the podcast and continue it from the iPhone without me having to pair the iPhone and the speaker.

I've found limited amounts of speakers or docks that have AirPlay but even with those, would it do what I want?