Stringers - Walking dissimilar lists to make comparisons

I have created an example to illustrate two dissimilar lists in 3D space that need to be compared. The lists have unequal length, branches, items in each branch, YET they share a common index, in this case an X value based on a STATION in the in X direction,

I have solved this kind of puzzle before with ~30 modules to align the branches of the lists, but I keep running into this issue.

Whats needed is a comparator that can take a branch as an input and then walk the items in that branch based on some criteria (in this instant case, X value) then execute an IF statement to create a numeric or boolean result. Obviously it requires nested loops.

This is equivalent to “find all instances in a list where X = n”
Is there a module like this?

using SORT and a matrix of values is really clunky

In this case example, all stringers from the lower set (curves) must be terminated at the nearest station such that they do NOT encroach into the upper set (curves)

ie: at each BRANCH (curve) in list 1, each of the ITEMS (points) must be compared based on its X location with a BRANCH from List 2 (curve) at the matching item (point) based on it X location.
IF the Z value is > then that point is DISPATCHED

For example at the last point on a station below the lowest curve from the upper set:

ff

Stringers 02.gh (18.4 KB)