Symfony：通过子域加载配置

How can I load custom config for subdomain in Symfony 3, for ex:
red.color.net:

    -ColorBundle
    --Resources
    ---config
    ----red.yml
    ----green.yml
    ----blue.yml

blue.color.net:

    -ColorBundle
    --Resources
    ---config
    ----red.yml
    ----green.yml
    ----blue.yml

In file

app/AppKernel.php

You have a method

public function registerContainerConfiguration(LoaderInterface $loader)
{
    $loader->load($this->getRootDir().'/config/config_'.$this->getEnvironment().'.yml');
}

You can modify its body to load any configuration file you need