Need Help Adjusting the Cost of a Set of Options

[AntaresCD]

Here's the situation:
-I have a set of items that are options for a unit.
-Said options are collected into a set using the candidate tag expression.
-I have a separate option, that if selected makes all of the previously mentioned options cheaper by a set amount (but no cheaper than a cost of 0).

What I want:
-To have the updated costs shown in the unit options pane.
-To have the updated costs shown in the output.
-To have the updated costs show in the selection window.

I have managed to get the first two by using a pre-link on the special option to assign a tag to the parent that is then checked for in the pre-link script of all the options that can have their cost reduced. Unfortunately, when the cost is reduced to 0, it doesn't show 0, it has no cost displayed. Also the selection screen shows the original costs.

I have a feeling that nothing short of overrides will adjust what is displayed in the selection screen (and overrides will not work here since I need entity level tags, not global tags), but maybe someone can point out a way.

Ideally, I wanted to put this in once (as opposed to doing it for all affected items), but the cost script for the option that gathers up the items into a set didn't work out for me.

I can live with the solution I have if I could get it to actually display the cost of 0 in the unit options on the side (non-zero values display properly) since other than this one quibble it reflects correctly in the output and unit options (I can live without it showing the new cost in the selection pane if that can't be done).

Thanks,

~Antares