Laravel Validator AND / require a field ONLY if both conditions are met

Using Laravel 5.1, is there a way to require a field ONLY if both conditions are met?

In the code example below, in the rules, I have field2_en and field2_de. I put 2 required_if rules for each field, the field becomes required if 1 of the 2 OR both required_if rules is/are met. It's not what I want. Here is what I want:

• I would like field2_en to be required ONLY if language = en AND radiobutton = 2
• I would like field2_de to be required ONLY if language = de AND radiobutton = 2

AddRequest.php

namespace App\Http\Requests\Post;

use App\Http\Requests\Request;

class AddRequest extends Request
{

    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return auth();
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        return [
            'language'              => ['required', 'in:en,de'],
            'field1_en'             => ['required_if:language,en'],
            'field1_de'             => ['required_if:language,de'],
            'radiobutton'           => ['required', 'in:1,2'],
            'field2_en'             => ['required_if:language,en', 'required_if:radio,2'],
            'field2_de'             => ['required_if:language,de', 'required_if:radio,2']
        ];
    }
}

I have been able to do it with sometimes() like below or with extend, but I wanted to know if there was other ways of doing it since I am using laravel-jsvalidation plugin and it doesn't work with such sometimes conditional validations.

protected function getValidatorInstance()
{
    $validator = parent::getValidatorInstance();

    $validator->sometimes('field2_en', 'required|min:2', function($input)
    {
        return ($input->language == 'en' && $input->radiobutton == '2');
    });

    ...

    return $validator;
}

via Chebli Mohamed