diff --git a/src/Constants.php b/src/Constants.php
index 33d931f..0e22863 100644
--- a/src/Constants.php
+++ b/src/Constants.php
@@ -16,6 +16,16 @@ class Constants
      */
     const MODULE_SLUG = 'nails/module-cdn';
 
-    const MEDIA_MANAGER_V1 = 1;
-    const MEDIA_MANAGER_V2 = 2;
+    const MEDIA_MANAGER_V1     = 1;
+    const MEDIA_MANAGER_V1_URL = 'admin/cdn/mediaManagerV1';
+
+    const MEDIA_MANAGER_V2     = 2;
+    const MEDIA_MANAGER_V2_URL = 'admin/cdn/mediaManagerV2';
+
+    /**
+     * Validation rules provided by this module (see src/Validation/Rule)
+     */
+    const RULE_OBJECT_PICKER_MULTI_ALL_REQUIRED    = 'cdnObjectPickerMultiAllRequired';
+    const RULE_OBJECT_PICKER_MULTI_LABEL_REQUIRED  = 'cdnObjectPickerMultiLabelRequired';
+    const RULE_OBJECT_PICKER_MULTI_OBJECT_REQUIRED = 'cdnObjectPickerMultiObjectRequired';
 }
diff --git a/src/Validation/Rule/CdnObjectPickerMultiAllRequired.php b/src/Validation/Rule/CdnObjectPickerMultiAllRequired.php
new file mode 100644
index 0000000..715ff4c
--- /dev/null
+++ b/src/Validation/Rule/CdnObjectPickerMultiAllRequired.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Nails\Cdn\Validation\Rule;
+
+use Nails\Common\Validation\AbstractRule;
+use Nails\Common\Validation\Context;
+
+/**
+ * Rule: `cdnObjectPickerMultiAllRequired` — every item in a CDN Object Multi Picker must have both an object and a label set
+ */
+class CdnObjectPickerMultiAllRequired extends AbstractRule
+{
+    public const NAME            = 'cdnObjectPickerMultiAllRequired';
+    public const DEFAULT_MESSAGE = 'All items must have a file and a label set.';
+
+    public function acceptsArrays(): bool
+    {
+        return true;
+    }
+
+    public function apply(mixed $mValue, Context $oContext): bool
+    {
+        if (!is_array($mValue)) {
+            return false;
+        }
+
+        foreach ($mValue as $aValue) {
+            if (!is_array($aValue) || empty($aValue['object_id']) || empty($aValue['label'])) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}
diff --git a/src/Validation/Rule/CdnObjectPickerMultiLabelRequired.php b/src/Validation/Rule/CdnObjectPickerMultiLabelRequired.php
new file mode 100644
index 0000000..0200215
--- /dev/null
+++ b/src/Validation/Rule/CdnObjectPickerMultiLabelRequired.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Nails\Cdn\Validation\Rule;
+
+use Nails\Common\Validation\AbstractRule;
+use Nails\Common\Validation\Context;
+
+/**
+ * Rule: `cdnObjectPickerMultiLabelRequired` — every item in a CDN Object Multi Picker must have a label set
+ */
+class CdnObjectPickerMultiLabelRequired extends AbstractRule
+{
+    public const NAME            = 'cdnObjectPickerMultiLabelRequired';
+    public const DEFAULT_MESSAGE = 'All items must have a label set.';
+
+    public function acceptsArrays(): bool
+    {
+        return true;
+    }
+
+    public function apply(mixed $mValue, Context $oContext): bool
+    {
+        if (!is_array($mValue)) {
+            return false;
+        }
+
+        foreach ($mValue as $aValue) {
+            if (!is_array($aValue) || empty($aValue['label'])) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}
diff --git a/src/Validation/Rule/CdnObjectPickerMultiObjectRequired.php b/src/Validation/Rule/CdnObjectPickerMultiObjectRequired.php
new file mode 100644
index 0000000..82c6b2a
--- /dev/null
+++ b/src/Validation/Rule/CdnObjectPickerMultiObjectRequired.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Nails\Cdn\Validation\Rule;
+
+use Nails\Common\Validation\AbstractRule;
+use Nails\Common\Validation\Context;
+
+/**
+ * Rule: `cdnObjectPickerMultiObjectRequired` — every item in a CDN Object Multi Picker must have an object set
+ */
+class CdnObjectPickerMultiObjectRequired extends AbstractRule
+{
+    public const NAME            = 'cdnObjectPickerMultiObjectRequired';
+    public const DEFAULT_MESSAGE = 'All items must have a file set.';
+
+    public function acceptsArrays(): bool
+    {
+        return true;
+    }
+
+    public function apply(mixed $mValue, Context $oContext): bool
+    {
+        if (!is_array($mValue)) {
+            return false;
+        }
+
+        foreach ($mValue as $aValue) {
+            if (!is_array($aValue) || empty($aValue['object_id'])) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}