Force block input order

I'm trying to use three inputs to create an interpolated curve.

But it simple won't interpolate in the correct order and I am unable to do anything about it. I'll try to illustrate with the image below. I want the curve to be interpolated in the order 1-2-3. But Grasshopper will automatically order them 2-1-3 for example. How do I change the input order of a block?

Image (not a working example):

EDIT: Got it fixed by sorting input by z-coordinate