Craft CMS 3 - Set activation and reset password emails urls according to user group or site

index.php

<?php

Event::on(
    \craft\records\User::class,
    \craft\records\User::EVENT_AFTER_UPDATE,
    static function (\yii\db\AfterSaveEvent $event) {
        $userRecord = $event->sender;
        $user = Craft::$app->getUsers()->getUserById($userRecord->id);
        $sites = Craft::$app->getSites();
        if ($user->isInGroup('user')) {
            $sites->setCurrentSite($sites->getSiteByHandle('sitehandle'));
        }
    }
);

Event::on(
    UsersController::class,
    UsersController::EVENT_AFTER_ASSIGN_GROUPS_AND_PERMISSIONS,
    static function (UserEvent $event) {
        $user = $event->user;
        $sites = Craft::$app->getSites();
        if ($user->isInGroup('user')) {
            $sites->setCurrentSite($sites->getSiteByHandle('sitehandle'));
        }
    }
);