Use Global Scope in Laravel Validation Rule

In my Laravel 8 project I have an existing global scope bind to a model like so:

protected static function booted() {
    static::addGlobalScope(new CompanyScope());
}

I already know that you can add a local scope to a validation rule like this:

class ExpenseRequest extends FormRequest {
    protected function validationRules(): array {
        return [
            "attachment" => Rule::exists('files')->where(function ($query) {
                (new Expense())->scope($query);
            })
        ];
    }
}

I want to add the global scope to an "exists" rule, but didn't find anything about how to do this. Does somebody know how to do this?