Limiting/validating thing picks.

[EightBitz]

I have a list of things called "Links".
I set up a chooser_table in a portal that let's a user choose one of the links.
I also have a list of things called "Descriptors".
I have an ability called "Initial Link" that is bootstrapped by the descriptor.
Each descriptor is supposed to be able to pick from one of four links, but each descriptor will pick from a different set of four.

Some links apply to more than one descriptor.

What I would like to be able to do is, when the chooser table is displayed, either only display the four Links that apply to the chosen descriptor, or have only those four links display as valid.

I've tried using different tag expressions in the <candidate> element of the chooser table, but everything I've tried has given some some sort of error.

I've tried using the <prereq> element in a given link thing, but I can't find anyway to include an "or" operator.

I've tried using a validation script, but when the game compiles, I get an error about my reference to hero.findchild[Descriptor].field[name].text.

So I'm kinda lost here. So far, rubber-band troubleshooting has not worked, and cardboard Mathias has not worked.

Is it possible to do what I'd like to do?