group email account is system read only field

application/Espo/Classes/FieldProcessing/InboundEmail/IsSystemLoader.php

@@ -0,0 +1,27 @@
+<?php
+/**LICENSE**/
+
+namespace Espo\Classes\FieldProcessing\InboundEmail;
+
+use Espo\Core\FieldProcessing\Loader;
+use Espo\Core\FieldProcessing\Loader\Params;
+use Espo\Core\Utils\Config;
+use Espo\Entities\InboundEmail;
+use Espo\ORM\Entity;
+
+/**
+ * @implements Loader<InboundEmail>
+ */
+class IsSystemLoader implements Loader
+{
+    public function __construct(
+        private Config $config,
+    ) {}
+
+    public function process(Entity $entity, Params $params): void
+    {
+        $isSystem = $entity->getEmailAddress() === $this->config->get('outboundEmailFromAddress');
+
+        $entity->set('isSystem', $isSystem);
+    }
+}