mmrUser_B.php

<?php
class mmrUser_B extends Doctrine_Record 
{
    public function setUp() 
    {
        $this->hasMany('mmrGroup_B as Group', array('local' => 'user_id', 
                                      'foreign' => 'group_id',
                                      'refClass' => 'mmrGroupUser_B'));

    }

    public function setTableDefinition() 
    {
      // Works when 
        $this->hasColumn('id', 'string', 30, array (  'primary' => true));
        $this->hasColumn('name', 'string', 30);
    }
}