In that case, to do it with a plugin you'd want OnWebLogin, rather than OnManagerLogin.
But the simplest way to do it would be to have three separate login pages and tell the users to go to the appropriate one to log in. The other two would be duplicates of your existing Login page, but with the &loginResourceId value set to the ID of the page you want to send them to.
To do it from a single Login page would require a plugin (or a postHook for the Login snippet -- the plugin would be slightly easier to code and a little more efficient). Just create a plugin called "Redirect Login" (or whatever, the name is arbitrary) with this code:
<?php
$userName = $user->get('username');
/* specify the page the user will be sent to */
switch ($userName) {
case 'bob':
$page = 7;
break;
case 'sally':
$page = 12;
break;
case 'jim':
$page = 22;
break;
/* anyone else */
default:
$page = 99;
break;
}
/* send them there */
$url = $modx->makeUrl($page, "", "", 'full');
$modx->sendRedirect($url);
Change the page IDs to the actual IDs of the pages you want to send them to (shown in parentheses after the name in the Resource tree in the Manager). Change the usernames to the actual usernames -- be sure to get the spelling right because they are case-sensitive.
If you need to send more than one user to the same page, you can "stack" the case statements like this:
case 'bob':
case 'fred':
case 'mary':
page = 35;
break;
On the System Events tab of the plugin, check the box next to OnWebLogin and save the plugin.
