So, I believe you have a good knowledge of the programming.
For your need, I believe you should create another snippet that will run if the user is successfully logged in and redirect to which page for that person.
Let’s say we call it ’redirectAfterLogin’ snippet, and put this after the Login snippet is called.
<?php // highlighting
/* not logged in */
if (!$modx->isAuthenticated())
return ''; // just return empty
/* logged in */
$userGroups = $modx->getUserGroups(); // an array of the groups that belongs to the logged in user
/* example of group redirects */
switch(in_array($userGroups)) {
case 'Director':
$redirectPage = '2';
case 'Manager':
$redirectPage = '3';
case 'Staff':
$redirectPage = '4';
default:
$redirectPage = '0';
}
$redirectPage = $modx->makeUrl($redirectPage); // just to make it FURL or not, depends on your setting
$modx->sendRedirect($redirectPage);
?>
Develop this further for the user that belongs to some multiple groups