That's hard to do. Even with Bluetooth 2.0. It depends mostly on your device, but most phone manufacturers don't see the need of multicast bluetooth pairing. Maybe try an FM transmitter. It hooks into your headphone jack and acts like a mini radio broadcast station. Then you can tune as many FM receiver devices as you want to that frequency and you're golden. I haven't done much digging here, but there might be an app that does multiple bluetooth devices. However, again, I'm quite certain phone manufacturers don't have this in default settings.
If the speakers have 3.5mm input and output on them then you could use a dual male sided cable and piggy back one speaker from the other. Other than that I don't know of any way as I've never done it or had the need myself.