Reordering options dynamically, based on values in a previous step

Problem/Motivation

I'm creating a multi-step webform.
On the second step, I need to dynamically adjust the options (reorder and remove some items) based on the values submitted in the first step.

Clearly I'd need some custom plugin to do this, and that's fine.
I'm just unsure where to start.

The logic required to sort/remove items is pretty convoluted, involving some calculations of values submitted in first step.

Is this even possible?

Thanks!