diff --git a/code/FileSubsites.php b/code/FileSubsites.php
index 3087685..54da090 100755
--- a/code/FileSubsites.php
+++ b/code/FileSubsites.php
@@ -5,15 +5,16 @@
  * @package subsites
  */
 class FileSubsites extends DataObjectDecorator {
+	
 	function extraStatics() {
-		// This is hard-coded to be applied to SiteTree, unfortunately
-        if($this->owner->class == 'File') {
-			return array(
-				'has_one' => array(
-					'Subsite' => 'Subsite',
-				),
-			);
+		if(!method_exists('DataObjectDecorator', 'load_extra_statics')) {
+			if($this->owner->class != 'File') return null;
 		}
+		return array(
+			'has_one' => array(
+				'Subsite' => 'Subsite',
+			),
+		);
 	}
 
 	/**
diff --git a/code/GroupSubsites.php b/code/GroupSubsites.php
index bb03146..5503dc3 100644
--- a/code/GroupSubsites.php
+++ b/code/GroupSubsites.php
@@ -7,14 +7,14 @@
 class GroupSubsites extends DataObjectDecorator {
 
 	function extraStatics() {
-		// This is hard-coded to be applied to SiteTree, unfortunately
-		if($this->owner->class == 'Group') {
-			return array(
-				'has_one' => array(
-					'Subsite' => 'Subsite',
-				),
-			);
+		if(!method_exists('DataObjectDecorator', 'load_extra_statics')) {
+			if($this->owner->class != 'Group') return null;
 		}
+		return array(
+			'has_one' => array(
+				'Subsite' => 'Subsite',
+			),
+		);
 	}
 
 	function updateCMSFields(&$fields) {
diff --git a/code/SiteTreeSubsites.php b/code/SiteTreeSubsites.php
index be72efc..7ef36cb 100644
--- a/code/SiteTreeSubsites.php
+++ b/code/SiteTreeSubsites.php
@@ -28,15 +28,15 @@ class SiteTreeSubsites extends DataObjectDecorator {
 
 	
 	function extraStatics() {
-		// This is hard-coded to be applied to SiteTree, unfortunately
-		if($this->owner->class == 'SiteTree') {
-			return array(
-				'has_one' => array(
-					'Subsite' => 'Subsite', // The subsite that this page belongs to
-					'MasterPage' => 'SiteTree', // Optional; the page that is the content master
-				),
-			);
+		if(!method_exists('DataObjectDecorator', 'load_extra_statics')) {
+			if($this->owner->class != 'SiteTree') return null;
 		}
+		return array(
+			'has_one' => array(
+				'Subsite' => 'Subsite', // The subsite that this page belongs to
+				'MasterPage' => 'SiteTree', // Optional; the page that is the content master
+			)
+		);
 	}
 	
 	/**