VSCode Code-Snippets transform

I have this:

${1/([A-Z]*)(?:_)([A-Z]+)*/${1:/downcase}${2:/downcase}/g}

How to make use downcase and capitalize on the same (2) group?

${1/([A-Z]*)(?:_)([A-Z]+)*/${1:/downcase}${2:/downcase/capitalize}/g}

I want to get ZXC_ASD > zxcAsd.