Cakephp Multiple hasAndBelongsToMany HABTM

I have a table Tasks_Users with id, task_id,user_id and sender_id. Problem is user_id and sender_id are both referring to facebook_id in Users table and I'm not sure how I can hook them together with two foreign keys. Is there a way we can get two foreign keys defined with HABTM relationship from one column?

UPDATE: Below is what I have currently set up in my Task model.

var $hasAndBelongsToMany = array(
        'User' => array(
            'className' => 'User',
            'joinTable' => 'tasks_users',
            'foreignKey' => 'task_id',
            'associationForeignKey' => 'user_id',
            'unique' => true,
            'conditions' => '',
            'fields' => '',
            'order' => '',
            'limit' => '',
            'offset' => '',
            'finderQuery' => '',
            'deleteQuery' => '',
            'insertQuery' => ''
        ),
        'Sender' => array(
            'className' => 'User',
            'joinTable' => 'tasks_users',
            'foreignKey' => 'task_id',
            'associationForeignKey' => 'sender_id',
            'unique' => true,
            'conditions' => '',
            'fields' => '',
            'order' => '',
            'limit' => '',
            'offset' => '',
            'finderQuery' => '',
            'deleteQuery' => '',
            'insertQuery' => ''
        )
    );

Below is for User model

var $hasAndBelongsToMany = array(
        'Task' => array(
            'className' => 'Task',
            'joinTable' => 'tasks_users',
            'foreignKey' => 'user_id',
            'associationForeignKey' => 'task_id',
            'unique' => true,
            'conditions' => '',
            'fields' => '',
            'order' => '',
            'limit' => '',
            'offset' => '',
            'finderQuery' =开发者_StackOverflow中文版> '',
            'deleteQuery' => '',
            'insertQuery' => ''
        )
    );

Below is TasksUser model

var $belongsTo = array(
        'Task' => array(
            'className' => 'Task',
            'foreignKey' => 'task_id',
            'conditions' => '',
            'fields' => '',
            'order' => ''
        ),
        'User' => array(
            'className' => 'User',
            'foreignKey' => 'user_id',
            'conditions' => '',
            'fields' => '',
            'order' => ''
        ),
        'Sender' => array(
            'className' => 'User',
            'foreignKey' => 'sender_id',
            'conditions' => '',
            'fields' => '',
            'order' => ''
        )
    );

I managed to get two multi-select boxes one for User_id and the other for Sender_id but the problem is I cannot save both at the same time for the same row...

The data arrays come as like this $this->data['User']['User'][] and $this->data['Sender']['Sender'][]

Theoretically it should save both but unfortunately it only saves Sender_id in the TasksUser table when you save using add action in scaffolding for Tasks controller and saves only User_id in the TasksUser table when you save using add action in scaffolding for Users controller.

The TasksUser tables are as below:

id  task_id   user_id   sender_id

How can I make it so it saves both user_id and sender_id at the same row???

---

You have to put bellow code in your controller,

 $this->TaskUser->bindModel(
            array('belongsTo' => array(
            'User1' => array(
            'className' => 'User',
            'foreignKey' => 'user_id'),

            'User2' => array(
            'className' => 'User',
            'foreignKey' => 'sender_id'),
                  )
               )
            );

---

It should work normally, I mean without any other correction: If you have a table User which relates via HABTM to other tables, when you make a saveAll CakePhp should automatically update the Join table. For me it does work.