Zend Framework 2 - Multiple subdomains create problems

I am writing an application in Zend Framework 2 that will run from several different subdomains, and I want to have a different module for each subdomain to keep things in order.

My problem is when I add more than 1 subdomain to the routing it loses one of the subdomains.

For example: this setting works testbed.localhost (module / app) a.testbed.localhost (module / A)

If I add an additional one, it will route all requests for a to the app index controller

e.g. testbed.localhost (module / application), a.testbed.localhost (module / A), b.testbed.localhost (module / B)

This is the .config.php module for the / A module

    'router' => array(
    'routes' => array(
        'ads' => array(
            'type'    => 'Hostname',
            'options' => array(
                 'route'    => 'a.testbed.localhost', 
                'constraints' => array(
                    'action' => '[a-zA-Z][a-zA-Z0-9_-]*',
                    'id'     => '[0-9]+',
                ),
                'defaults' => array(
                    '__NAMESPACE__' => 'A\Controller',
                    'controller' => 'A\Controller\A',
                    'action'     => 'index',
                ),
            ),

      

        
        
        
      

    

And this is the route to module.config.php in module / B

    'router' => array(
    'routes' => array(
        'ads' => array(
            'type'    => 'Hostname',
            'options' => array(
                 'route'    => 'b.testbed.localhost', 
                'constraints' => array(
                    'action' => '[a-zA-Z][a-zA-Z0-9_-]*',
                    'id'     => '[0-9]+',
                ),
                'defaults' => array(
                    '__NAMESPACE__' => 'B\Controller',
                    'controller' => 'B\Controller\B',
                    'action'     => 'index',
                ),
            ),

      

        
        
        
      

    

Now the namespaces are correct in the module.config.php files, I noticed that the a.testbed.localhost subdomain will work if I remove the reference to it from config / application.config.php

    <?php
    return array(
        'modules' => array(
         'Application',
         'A',
         'B', <--- A doesn't work if B is here
      ),

      

        
        
        
      

    

And if I swap A and B around in the modules array above, then B will be redirected to Application Module and A will work. So it seems to be having more than one subdomain problem. Anyone got any ideas / came across the same thing?