How to link multiple keys to different sliders in After Effects

Question

I'm a newbie with After Effects expressions, I need help with link few keyframes to different sliders on Null. I found this expression and its work with 2 keypoints.

if (numKeys > 1){
  t1 = key(1).time;
  t2 = key(2).time;
  v1 = 0;
  v2 = effect("Slider Control")("Slider");
  linear(time,t1,t2,v1,v2);
}else value

But how to link keyframe to slide if there a more then 2 keyframes.

thank you