Magento 2.2.5, Is possible to restrict place order based on the customer group?

Question

In Magento 2.2.5, I need to restrict place order for some customers who assigned to certain group. Is any possibility to restrict place order based on the customer group?

Answer 1

You could use Payment Restrictions which restricts and doesn't allow any payment method for customer group which you want to block.

Answer 2

Try following way, when place order in review page there has checking customer group. Customer groups come from settings or you can hard code the group id.

app/code/SR/MagentoStackExchange/etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Checkout\Api\PaymentInformationManagementInterface">
        <plugin name="disable-place-order" type="SR\MagentoStackExchange\Plugin\PaymentInformationManagement"/>
    </type>
    <type name="Magento\Checkout\Api\GuestPaymentInformationManagementInterface">
        <plugin name="disable-guest-place-order" type="SR\MagentoStackExchange\Plugin\GuestPaymentInformationManagement"/>
    </type>
</config>

app/code/SR/MagentoStackExchange/Model/Config.php

<?php
namespace SR\MagentoStackExchange\Model;

use Magento\Framework\App\Config\ScopeConfigInterface;
use Magento\Quote\Api\CartRepositoryInterface;

class Config
{
    /**
     * @var ScopeConfigInterface
     */
    private $scopeConfig;

    /**
     * @var CartRepositoryInterface
     */
    private $cartRepository;

    /**
     * Config constructor.
     *
     * @param ScopeConfigInterface $scopeConfig
     * @param CartRepositoryInterface $cartRepository
     */
    public function __construct(
        ScopeConfigInterface $scopeConfig,
        CartRepositoryInterface $cartRepository
    ) {
        $this->scopeConfig = $scopeConfig;
        $this->cartRepository = $cartRepository;
    }

    public function isAllowPlaceOrder($cartId)
    {
        /** @var \Magento\Quote\Model\Quote $quote */
        $quote = $this->cartRepository->getActive($cartId);
        $customer = $quote->getCustomer();
        // group ID come from settings or set 1 or 2 or 3 that you want
        $restrictGroup = $this->scopeConfig->getValue('magento_stack_exchange\general\restrict_group');
        if ($restrictGroup == $customer->getGroupId()) {
            return false;
        }

        return true;
    }
}

app/code/SR/MagentoStackExchange/Plugin/PaymentInformationManagement.php

<?php
namespace SR\MagentoStackExchange\Plugin;

use Magento\Checkout\Api\PaymentInformationManagementInterface;
use Magento\Framework\Exception\LocalizedException;
use SR\MagentoStackExchange\Model\Config;
use Magento\Quote\Api\Data\PaymentInterface;
use Magento\Quote\Api\Data\AddressInterface;

/**
 * Class PaymentInformationManagement
 */
class PaymentInformationManagement
{
    /**
     * @var Config
     */
    private $config;

    /**
     * PaymentInformationManagement constructor.
     *
     * @param Config $config
     */
    public function __construct(Config $config)
    {
        $this->config = $config;
    }

    /**
     * Disable order submitting
     *
     * @param PaymentInformationManagementInterface $subject
     * @param int $cartId
     * @param PaymentInterface $paymentMethod
     * @param AddressInterface|null $billingAddress
     * @return void
     * @throws LocalizedException
     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
     */
    public function beforeSavePaymentInformationAndPlaceOrder(
        PaymentInformationManagementInterface $subject,
        $cartId,
        PaymentInterface $paymentMethod,
        AddressInterface $billingAddress = null
    ) {
        if ($this->config->isAllowPlaceOrder($cartId)) {
            throw new LocalizedException(__("The order can't be submitted."));
        }
    }
}

app/code/SR/MagentoStackExchange/Plugin/GuestPaymentInformationManagement.php

<?php
namespace SR\MagentoStackExchange\Plugin;

use Magento\Checkout\Api\GuestPaymentInformationManagementInterface;
use Magento\Framework\Exception\LocalizedException;
use Magento\Quote\Api\Data\AddressInterface;
use Magento\Quote\Api\Data\PaymentInterface;
use SR\MagentoStackExchange\Model\Config;

/**
 * Class GuestPaymentInformationManagement
 */
class GuestPaymentInformationManagement
{
    /**
     * @var Config
     */
    private $config;

    /**
     * PaymentInformationManagement constructor.
     *
     * @param Config $config
     */
    public function __construct(Config $config)
    {
        $this->config = $config;
    }

    /**
     * Disable order submitting
     *
     * @param GuestPaymentInformationManagementInterface $subject
     * @param string $cartId
     * @param string $email
     * @param PaymentInterface $paymentMethod
     * @param AddressInterface|null $billingAddress
     * @return void
     * @throws LocalizedException
     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
     */
    public function beforeSavePaymentInformationAndPlaceOrder(
        GuestPaymentInformationManagementInterface $subject,
        $cartId,
        $email,
        PaymentInterface $paymentMethod,
        AddressInterface $billingAddress = null
    ) {
        if ($this->config->isAllowPlaceOrder($cartId)) {
            throw new LocalizedException(__("The order can't be submitted."));
        }
    }
}