Vertical passive bi amping

I'm currently running a pair of Infinity speakers this way with two Dynaco ST120's. I've recently purchased a pair of original Klipsch Heresys and would like to do the same with these. The binding posts are not set up for this but changing the crossover into seperate high pass and low pass filters seems like a simple enough task. My question concerns issues with changing the impedence curve and possibly blowing out one channel in the amps. Is there some fundamental design change that allow my Infinitys to work this way that my Klipsch speakers don't have?

Martin