Multiple sweeps

I'm trying to sweep a list of surfaces through a list of rails (which are curves).I made sure that the list correspond (1 surface -> first rail etc) but still it won't sweep them.The only way I can get a visual response is when I "Graft" the Surface Parameter;but the result is that each surface is sweep on each rail(ex having 10 surface and 10 rail I get 100 sweeps).What is wrong?

thanks for the help