I need some choosers' contents to delete themselves if the race changes

[Mathias]

Still working on the same piece of the Dark heresy game - each career option offers 0-3 pairs of skills for the user to select between using choosers. The choosers get their list of available skills from fields on the hero. These fields are set by a script on the career component.

The problem I'm running into is when the user decides on a different career - how do I get the picks added by these choosers to delete themselves when the race changes?

An existence tag seems like the way to do it, but I can't figure out a tag expression that I could use to track whether the race changed.

Perhaps a change script on the chooser for the race? There's already a tag being assigned to the skills added by these choosers and nowhere else - do I search through the list of skills and delete the ones with that tag whenever the race changes?