profile_view:
  url:   /:username
  host:  /^(www)?\.domain\.com/
  param: { module: family, action: view }

group_view:
  url:   /:groupname
  host:  /^(www)?(^\.+)\.domain\.com/
  param: { module: family, action: view, hostkeys: street }
  # $this->getRequestParameter('street') should equal whatever came out from the "(^\.+)" regex token.

signin:
  url:   /signin
  host:  domain.com  #no wildcards means this is required for reverse linking
  param: { module: sfUserAuth, action: signin }

user_view:
  url:    /:username
  host:  /^(www)?\.(.+$)/  # means that the host can be www.domain.com or domain.com
  param: { module: profile, action: view }
  
family_view:
  url:   /:family
  host:  /^((?:(?:[^\.]+)?))\.(.+$)/  # means that the host can be anything.domain.com
  host_matches: { familygroup: 1 }
  param: { module: family, action: view }

public function getMatchingRule()
{
  if (preg_match($rule['host'], $req->getHost(), $matches))
  {
    if (count($matches) > 1)
    {
      // this rule matched
      foreach ($rule['host_matches'] as $k => $v)
      {
        $this->setRequestParameter($k, $matches[$v]);
      }
    }
    else
    {
      // didn't match.. move onto next rule
    }
  }
}

public function getUrlForRule($rulename)
{
  $rule = Rules::getByRuleName($rulename);
  if ($rule['host'])
  {
    if (substr($rule['host'], 0, 1) == '/')
    {
      // host isn't a regex, force it
      return 'http://' . $rule['host'] . '/' . $extra_path_stuff;
    }
    else if (preg_match($rule['host'], $req->getHost(), $matches))
    {
      // do some mumbo jumbo to parse the parameters and such to make the URL.  The important part is the current host matches the rule host
    }
    else
    {
      // doesn't match. return something incorrect
    }
  }
  else
  {
    // no host in the rule.. make the url relative
    return '/' . $extra_path_stuff;
  }
}

// current url is 
http://subdomain1.domain.com/family
echo link_to('@family_view?family=babineau')
=> http://subdomain1.domain.com/babineau

// current url is 
http://subdomain1.domain.com/family
echo link_to('@signin')
=> http://domain.com/signin

myrule:
  url: /:module/:action/:host

signin:
  url:   /signin
  host:  domain.com
  param: { module: sfUserAuth, action: signin }

user_view_www:
  url:    /:username
  host:   www.domain.com
  param: { module: profile, action: view }

user_view:
  url:    /:username
  host:   domain.com
  param: { module: profile, action: view }
  
family_view_www:
  url:   /:family
  host:  www.:familygroup.domain.com
  param: { module: family, action: view }

family_view:
  url:   /:family
  host:  :familygroup.domain.com
  param: { module: family, action: view }

# any host goes
any_domain_rule:
  url:   /*
  param: { module: default, action: index }