THe only problem with that (as I mentioned earlier) is I'm not sure what happens if the sensor sees both beacons at the same time, then you end up seeing some strange superimposing of the two (or beat frequencies or whatever). The beacons are probably not synchronized to each other either. You could code it so that if it was a funny reading that wasn't exactly clear cut, you would assume you were reading both beacons at the same time. Simple is good. Try it out. You might be pleasantly suprised.