diff --git a/src/Bundle/ChillMainBundle/Entity/UserGroup.php b/src/Bundle/ChillMainBundle/Entity/UserGroup.php
index b42609693..b39216b11 100644
--- a/src/Bundle/ChillMainBundle/Entity/UserGroup.php
+++ b/src/Bundle/ChillMainBundle/Entity/UserGroup.php
@@ -18,9 +18,12 @@ use Doctrine\Common\Collections\Order;
 use Doctrine\Common\Collections\ReadableCollection;
 use Doctrine\Common\Collections\Selectable;
 use Doctrine\ORM\Mapping as ORM;
+use Symfony\Component\Serializer\Annotation\DiscriminatorMap;
 
 #[ORM\Entity]
 #[ORM\Table(name: 'chill_main_user_group')]
+// this discriminator key is required for automated denormalization
+#[DiscriminatorMap('type', mapping: ['user_group' => UserGroup::class])]
 class UserGroup
 {
     #[ORM\Id]
@@ -65,7 +68,7 @@ class UserGroup
 
     public function __construct()
     {
-        $this->adminUsers = new \Doctrine\Common\Collections\ArrayCollection();
+        $this->adminUsers = new ArrayCollection();
         $this->users = new ArrayCollection();
     }
 
diff --git a/src/Bundle/ChillMainBundle/Form/Type/DataTransformer/EntityToJsonTransformer.php b/src/Bundle/ChillMainBundle/Form/Type/DataTransformer/EntityToJsonTransformer.php
index 737c4683f..c6839efa8 100644
--- a/src/Bundle/ChillMainBundle/Form/Type/DataTransformer/EntityToJsonTransformer.php
+++ b/src/Bundle/ChillMainBundle/Form/Type/DataTransformer/EntityToJsonTransformer.php
@@ -13,6 +13,7 @@ namespace Chill\MainBundle\Form\Type\DataTransformer;
 
 use Chill\MainBundle\Entity\User;
 use Chill\MainBundle\Entity\UserGroup;
+use Chill\MainBundle\Serializer\Normalizer\DiscriminatedObjectDenormalizer;
 use Chill\PersonBundle\Entity\Person;
 use Chill\ThirdPartyBundle\Entity\ThirdParty;
 use Symfony\Component\Form\DataTransformerInterface;
@@ -76,15 +77,22 @@ class EntityToJsonTransformer implements DataTransformerInterface
             'person' => Person::class,
             'thirdparty' => ThirdParty::class,
             'user_group' => UserGroup::class,
+            'user_group_or_user' => DiscriminatedObjectDenormalizer::TYPE,
             default => throw new \UnexpectedValueException('This type is not supported'),
         };
 
+        $context = [AbstractNormalizer::GROUPS => ['read']];
+
+        if ('user_group_or_user' === $this->type) {
+            $context[DiscriminatedObjectDenormalizer::ALLOWED_TYPES] = [UserGroup::class, User::class];
+        }
+
         return
             $this->denormalizer->denormalize(
                 ['type' => $item['type'], 'id' => $item['id']],
                 $class,
                 'json',
-                [AbstractNormalizer::GROUPS => ['read']],
+                $context,
             );
     }
 }
diff --git a/src/Bundle/ChillMainBundle/Form/Type/PickUserGroupOrUserDynamicType.php b/src/Bundle/ChillMainBundle/Form/Type/PickUserGroupOrUserDynamicType.php
index 00d783a97..c4e91cce4 100644
--- a/src/Bundle/ChillMainBundle/Form/Type/PickUserGroupOrUserDynamicType.php
+++ b/src/Bundle/ChillMainBundle/Form/Type/PickUserGroupOrUserDynamicType.php
@@ -30,7 +30,7 @@ final class PickUserGroupOrUserDynamicType extends AbstractType
 
     public function buildForm(FormBuilderInterface $builder, array $options)
     {
-        $builder->addViewTransformer(new EntityToJsonTransformer($this->denormalizer, $this->serializer, $options['multiple'], 'user_group'));
+        $builder->addViewTransformer(new EntityToJsonTransformer($this->denormalizer, $this->serializer, $options['multiple'], 'user_group_or_user'));
     }
 
     public function buildView(FormView $view, FormInterface $form, array $options)