Hmm.. I think I figured it out..
I don't know if this is necessary, but I edited the pb2ents_b5.c file in the ..\bsp\pball2\entity folder to include these lines:
/*QUAKED func_rotating (0 .5 8) ? START_ON REVERSE TOUCH_PAIN STOP
*/
Then I made my brushes, applied func_rotating, made the middle thing an Origin, etc. I included a cheesy map to demonstrate. Ignore the fact that the design, textures and lighting sucks.