This extension allows to show products to specified customer groups only. If the user does not belong to the group for which this product is available then the user will see 'Access denied' page.
Sales & Demo Page : https://www.opencart.com/index.php?route=marketplace/extension/info&extension_id=5130
Sales & Demo Page : https://www.opencart.com/index.php?route=marketplace/extension/info&extension_id=5130