Bluetooth idea

I've got some cheap BT speakers. They are cylinders about half as tall as a can of soup or veggies. The top is a speaker, and there's a mic on one side. So they can be used with a phone as a speaker-phone.

I've got a much better BT speaker now, but I got to thinking that if I could link to a BT device I could use the old ones as an intercom of sorts. Like for example hidden in some Halloween decorations.

Seems like overkill to tie up an entire computer for this. Anybody know if there's a gizmo/box I could use for this?