Separate Option Values - Set up hook if have different value

[Marco Ro]

Hi guys, I try to set up the option values for the options fields. Like it's write here: https://processwire.com/docs/fields/select-options-fieldtype/#separate-option-values

EG: I write 123=IT|Italy and render the option value <option value="IT">Italy</option>. I read that need to use $option->value. But I would like to step up a hook to show the custom value when this value exists, otherwise continue to show the ID. Is it possible? 

I try to work around FieldtypeOptions::formatValue(), but I don't know how setup this hook and if it is the correct way to do it.