Multi-point portable speakers

We had a party a few days ago out in our cul-de-sac and we didn't have any music for it... no one had a portable sound system they wanted to set up, so it got me thinking about getting a portable speaker setup that would connect to my (android) phone. And I wanted a setup with, say, four speakers, so that we didn't have to blast the music on one side of the road so that people on the opposite side of the road could hear it. I also want to be able to take one or two of the speakers out to the pool on the weekend so that I can play music there as well. So it has to be completely wireless and battery powered.



Bluetooth is point-to-point, so most portable speakers limit you to one speaker with that configuration, which rules most of those out. I came across HiddenRadio2, which seems to do what I want, but can't find any reviews.



Anyone have any insights or buying advice to share about portable speakers?