diff --git a/Classes/Resource/RemoteResourceCollectionFactory.php b/Classes/Resource/RemoteResourceCollectionFactory.php
index 43aa663..52d1c23 100644
--- a/Classes/Resource/RemoteResourceCollectionFactory.php
+++ b/Classes/Resource/RemoteResourceCollectionFactory.php
@@ -22,25 +22,24 @@
 class RemoteResourceCollectionFactory
 {
     /**
-     * @param string $configuration
+     * @param array $configuration
+     * @throws \RuntimeException
      * @return RemoteResourceCollection
      */
-    public static function createRemoteResourceCollectionFromConfiguration($configuration)
+    public static function createRemoteResourceCollectionFromConfiguration(array $configuration)
     {
         $remoteResources = [];
 
-        $resourcesConfiguration = GeneralUtility::xml2array($configuration);
-
-        foreach ((array)$resourcesConfiguration['data']['sDEF']['lDEF']['resources']['el'] as $resource) {
+        foreach ($configuration as $key => $resource) {
             if (empty($resource)) {
                 continue;
             }
 
-            $key = key($resource);
-
             switch ($key) {
                 case 'domain':
-                    $remoteResources[] = GeneralUtility::makeInstance(DomainResource::class, $resource['domain']['el']['domain']['vDEF']);
+                    foreach ($resource as $domain) {
+                        $remoteResources[] = GeneralUtility::makeInstance(DomainResource::class, $domain);
+                    }
                     break;
                 case 'sys_domain':
                     $domainResourceRepository = GeneralUtility::makeInstance(DomainResourceRepository::class);
@@ -56,4 +55,44 @@ public static function createRemoteResourceCollectionFromConfiguration($configur
 
         return GeneralUtility::makeInstance(RemoteResourceCollection::class, $remoteResources);
     }
+
+    /**
+     * @param string $flexForm
+     * @throws \RuntimeException
+     * @return RemoteResourceCollection
+     */
+    public static function createRemoteResourceCollectionFromFlexForm($flexForm)
+    {
+        $configuration = [];
+
+        $resourcesConfiguration = GeneralUtility::xml2array($flexForm);
+
+        foreach ((array)$resourcesConfiguration['data']['sDEF']['lDEF']['resources']['el'] as $resource) {
+            if (empty($resource)) {
+                continue;
+            }
+
+            $key = key($resource);
+
+            switch ($key) {
+                case 'domain':
+                    if (empty($configuration[$key])) {
+                        $configuration[$key] = [];
+                    }
+                    $configuration[$key] = array_merge(
+                        $configuration[$key],
+                        [$resource['domain']['el']['domain']['vDEF']]
+                    );
+                    break;
+                case 'sys_domain':
+                case 'placeholder':
+                    $configuration[$key] = true;
+                    break;
+                default:
+                    throw new \RuntimeException('Unexpected File Fill Resource configuration "' . $key . '"', 1528326468);
+            }
+        }
+
+        return self::createRemoteResourceCollectionFromConfiguration($configuration);
+    }
 }
diff --git a/Classes/Slot/ResourceFactorySlot.php b/Classes/Slot/ResourceFactorySlot.php
index b1db78e..e1c2582 100644
--- a/Classes/Slot/ResourceFactorySlot.php
+++ b/Classes/Slot/ResourceFactorySlot.php
@@ -26,10 +26,11 @@ class ResourceFactorySlot
     public function initializeResourceStorage(ResourceFactory $resourceFactory, ResourceStorage $resourceStorage)
     {
         $storageRecord = $resourceStorage->getStorageRecord();
-        if ($storageRecord['driver'] !== 'Local'
-            || empty($storageRecord['tx_filefill_enable'])
-            || empty($storageRecord['tx_filefill_resources'])
-        ) {
+        $isLocalDriver = $storageRecord['driver'] === 'Local';
+        $isRecordEnabled = !empty($storageRecord['tx_filefill_enable']) && !empty($storageRecord['tx_filefill_resources']);
+        $isStorageConfigured = !empty($GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['filefill']['storages'][$resourceStorage->getUid()]);
+
+        if (!$isLocalDriver || (!$isRecordEnabled && !$isStorageConfigured)) {
             return;
         }
 
@@ -38,9 +39,15 @@ public function initializeResourceStorage(ResourceFactory $resourceFactory, Reso
         }, null, ResourceStorage::class);
         $originalDriverObject = $closure();
 
-        $remoteResourceCollection = RemoteResourceCollectionFactory::createRemoteResourceCollectionFromConfiguration(
-            $storageRecord['tx_filefill_resources']
-        );
+        if ($isRecordEnabled) {
+            $remoteResourceCollection = RemoteResourceCollectionFactory::createRemoteResourceCollectionFromFlexForm(
+                $storageRecord['tx_filefill_resources']
+            );
+        } else {
+            $remoteResourceCollection = RemoteResourceCollectionFactory::createRemoteResourceCollectionFromConfiguration(
+                $GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['filefill']['storages'][$resourceStorage->getUid()]
+            );
+        }
 
         $driverObject = GeneralUtility::makeInstance(
             FileFillDriver::class,
diff --git a/README.md b/README.md
index 8dfe67b..06bf080 100644
--- a/README.md
+++ b/README.md
@@ -25,12 +25,32 @@ You only need to configure one or more existing "File Storage" records
 
 *Prerequisite: Only storages with a "Local filesystem" driver are currently supported.*
 
+### Database record configuration
+
 - go to the root of your TYPO3 page tree (id=0)
 - change to the list module (Web -> List on the left side)
 - find the "File Storage" section and edit a record
 - change to the tab "File Fill" and select the enable checkbox
 - define the resource chain that should be used to fetch missing files
 
+### TYPO3_CONF_VARS configuration
+
+- given a file storage with uid 1, the configuration might look like this
+
+```php
+$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['filefill']['storages'][1] = [
+    'domain' => [
+        'https://example.com',
+        'https://example.org',
+    ],
+    'sys_domain' => true,
+    'placeholder' => true,
+];
+```
+
+- you don't need to configure resources that you don't want to use
+- the ordering in your configuration defines the ordering of processing
+
 ## Resources
 
 Resources define the places (url / services) were filefill tries to fetch missing files from. You can use multiple