[TYPO3-mvc] adding objects inside loop

[Pieter Geurts - Aleto Internet]

Hello,
Why is the code below now working properly, it will only save the last 
banner inside the loop. Tried putting the persistAll() inside the loop, 
that made no difference

$groupArray = $this->request->getArgument('grouping');

         foreach($groupArray AS $key=>$value)
         {

         $group[$key] = $this->groupingRepository->findByUid($key);
         $group[$key]->addBanner($newBanner);
         }

     $persistenceManager = Tx_Extbase_Dispatcher::getPersistenceManager();
         $persistenceManager->persistAll();

grtz

Pieter