GreenfoodSound simply provides a way of playing and looping sound clips - it hasn't got any clever functionality that finds certain sounds, beats or rhythms (this is way beyond its scope) nor does it really allow you to get at any useful data in the sound file that could let you do this yourself. This would be quite a difficult project, but if you really did want to proceed you'd have to use another sound library that let you retrieve much more detailed data about the file it was playing (and from there you'd have have to do various non-trivial things such as peak locating or comb filtering before coming up with an algorithm to match beats and rhythms.) Not an easy task!