CakePHP 2: Override AuthComponent's "password" method

My goal is to have a unique salt for each user rather than just using Configure::read('Security.salt') for every user.

I know that CakePHP 2.x no longer hashes passwords automatically. This allows me to perform model validation on passwords, which is very nice. However, I don't see a way that I can override the AuthComponent's "password" method. So even though I can control how passwords are hashed before they are saved to the database, I cannot control how passwords are hashed when performing the actual login. From the cookbook:

You don’t need to hash passwords before calling $this->Auth->login().

What can I do to make $this->Auth->login() use a custom method of password hashing?

Thanks.

UPDATE: I ended up going with dr Hannibal Lecter's answer (creating a custom authentication object). Here's how to do it:

Old code:

$this->Auth->authenticate = array('Form' => array('fields' => array('username' => 'email')));

New code (change "Form" to "Custom"):

$this->Auth->authenticate = array('Custom' => array('fields' => array('username' => 'email')));

Create "app/Controller/Component/Auth/CustomAuthenticate.php" and make it look like this:

<?php
App::uses('FormAuthenticate', 'Controller/Component/Auth');

class CustomAuthenticate extends FormAuthenticate {
}

Copy the "_findUser" and "_password" methods from "lib/Cake/Controller/Component/Auth/BaseAuthenticate.php" and paste them into the "CustomAuthenticate" class. Then make the following two modifications to the "_findUser" method:

1. Remove this line from the "$conditions" array: $model . '.' . $fields['password'] => $this->_password($password),

2. Change if (empty($result) || empty($result[$model])) { to if (empty($result) || empty($result[$model]) || $result[$model][$fields['password']] != $this->_password($password, $result[$model]['id'])) {

Then make the following two modifications to the "_password" method:

1. Create the "$id" parameter by changing protected function _password($password) { to protected function _password($password, $id) {

2. Update the salt value by changing return Security::hash($password, null, true); to return Security::hash($password, null, Configure::read('Security.salt') . $id);

Lastly, update all occurrences of AuthComponent::password to use Security::hash with the same logic as above.