Custom race bonus

I am trying to make a custom race in the HL Editor that gets a choice of stat bonus between either DEX or CHA. But I cant figure out how to do that.
I see bootstraps available for similar either/or bonuses, but none with that exact combo.
Any suggestions?

So start from the Human racial ability that lets you add +2 to any ability score. That gives you 99% of the logic done. The difference is you need to create a custom expression for the dropdown to limit to only Dex and Cha.

See THIS thread about how to create a custom expression.

OK. so I found the Racial Special for Humans that allows the +2 to any Ability and I've made a new copy of that and renamed/edited the text to specify that the bonus only goes to DEX or CHA. So far so good.

But, the list to pick from still includes all of the attributes.

Now I need to figure out how to limit the choices in the ability pull-down only to DEX or CHA. There are so many TagIds and Group Names for the tags that affect attributes. I cant tell how they interact and what they do.
I'm in over my head here.

Go down to where it says "Custom Expression" and it currently has:
change it to be:

Awesome! Thanks so much!