Auto move user from verification to a specific usergroup under condition?

[Skyrider]

Is there anyway for me to add a PHP plugin code where a user has met a specific condition once they validated their email, it'll move him/her to another usergroup rather than the default registration group?

In this case, another plugin calls up $islinked is someone is linked or not. I'd like to have something that IF user $islinked and is in the email verification group that once he/she has his/her mail verified, that in combination with $islinked it'll move him to a specific usergroup.

EG:

if ($islinked) { && has just verified mail address -> move to usergroup

<if needed> add an ELSE code to continue normal verification to
registered usergroup if not islinked.

OR something like this:

if ($islinked) && ($vbulletin->options['verifyemail'])
	{
		$newusergroupid = X;
	}
	else
	{
		$newusergroupid = 2;
	}

from register.php. I don't mind including the additional files to make this work in the register PHP file.

// get special data templates from the datastore
$specialtemplates = array('steam_softlinks');

// pre-cache templates used by all actions
$globaltemplates = array(
	'register_rules',
	'register_verify_age',
);

// ######################### REQUIRE BACK-END ############################
require_once('./global.php');
require_once(DIR . '/includes/functions_login.php');
require_once(DIR . '/includes/openid.php');
require_once(DIR . '/includes/functions_steamconnect.php');

^ From the steam login system.

I greatly appreciated the help.