It's one connection at a time. Once connected the pucks don't continue advertising. There are a couple of other threads in the puck.js forum section, so you may have already found your answers. If not check this thread out http://forum.espruino.com/conversations/297154/#comment13362559
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
It's one connection at a time. Once connected the pucks don't continue advertising. There are a couple of other threads in the puck.js forum section, so you may have already found your answers. If not check this thread out http://forum.espruino.com/conversations/297154/#comment13362559