Big Sound Temple

What's the correct, collective noun for the above? A 'gaggle' of schoolgirls? Just had to take this picture, cause usually hogging the massaging electric chairs are a bunch of middle-aged women with their hair dyed that strange shade of purple.

Wife and baby were with me when I asked the girls if I could take their pic, so hopefully I didn't come across as being too much of a gaijin chikan ('foreign pervert'). I mean, gaijin are customarily viewed as being slightly suspect by many Japanese, regardless of how politely this is concealed, but still I suspect that there are limits.