api: Can't group routes using different prefixes

Q	A
Bug?	no
New Feature?	no
Framework	Laravel
Framework version	5.x.y
Package version	1.x.y
PHP version	5.x.y

Actual Behaviour

I’m trying to group different route groups with different prefixes, but in the end only one prefix group is working.

Expected Behaviour

$api = app('Dingo\Api\Routing\Router');

$api->group(['version' => 'v1', 'prefix' => 'auth', 'domain' => env('APP_DOMAIN'), 'namespace' => 'App\\Http\\Controllers'], function($api) {

    $api->version('v1', ['middleware' => ['throttle:40', 'api']], function ($api) {

        $api->post('login', 'AuthController@login');
        ... Routes...
     });
});

$api->group(['version' => 'v1', 'prefix' => 'main', 'domain' => env('APP_DOMAIN'), 'namespace' => 'App\\Http\\Controllers'], function($api) {

    $api->version('v1', ['middleware' => ['throttle:40', 'api']], function ($api) {

        $api->post('/cables',                           'CablesController@postCreate');
        ... Routes...
     });
});

How to solve this ? I need exactly this kind of solution, using same domain and different route groups defined by prefixes. Thanks