diff --git a/security/Group.php b/security/Group.php
index 375225e81..84d7b9870 100644
--- a/security/Group.php
+++ b/security/Group.php
@@ -331,8 +331,11 @@ class Group extends DataObject {
 	function onBeforeWrite() {
 		parent::onBeforeWrite();
 		
-		if(stripos($this->Code, _t('SecurityAdmin.NEWGROUPPREFIX','new-')) === 0) {
-			$this->setCode($this->Title);
+		// Only set code property when the group has a custom title, and no code exists.
+		// The "Code" attribute is usually treated as a more permanent identifier than database IDs
+		// in custom application logic, so can't be changed after its first set.
+		if(!$this->Code && $this->Title != _t('SecurityAdmin.NEWGROUP',"New Group")) {
+			if(!$this->Code) $this->setCode($this->Title);
 		}
 	}
 	
diff --git a/tests/security/GroupTest.php b/tests/security/GroupTest.php
index a16facd51..009511dee 100644
--- a/tests/security/GroupTest.php
+++ b/tests/security/GroupTest.php
@@ -4,8 +4,27 @@
  * @subpackage tests
  */
 class GroupTest extends FunctionalTest {
+
 	static $fixture_file = 'GroupTest.yml';
 	
+	function testGroupCodeDefaultsToTitle() {
+		$g1 = new Group();
+		$g1->Title = "My Title";
+		$g1->write();
+		$this->assertEquals('my-title', $g1->Code, 'Custom title gets converted to code if none exists already');
+		
+		$g2 = new Group();
+		$g2->Title = "My Title";
+		$g2->Code = "my-code";
+		$g2->write();
+		$this->assertEquals('my-code', $g2->Code, 'Custom attributes are not overwritten by Title field');
+		
+		$g3 = new Group();
+		$g3->Title = _t('SecurityAdmin.NEWGROUP',"New Group");
+		$g3->write();
+		$this->assertNull($g3->Code, 'Default title doesnt trigger attribute setting');
+	}
+	
 	/**
 	 * Test the Group::map() function
 	 */