Anyway, CLIPS is written in C, so it should be somehow posible to handle it via php.
little offtopic:
But anyway, its very hard to test/debug clips/jess..
Its interesting to me, in what stage of fulfilling your vision You are?
actaally, what You want, is some kind of very advanced lesson module .., am I right?
Just resources wouldn't help in your case, as they don't propose any choice (according to whitch Your agents would choose what to teach next..), and resources can't be graded..