diff --git a/app/V1Module/presenters/GroupsPresenter.php b/app/V1Module/presenters/GroupsPresenter.php
index ef2bad19..bd059805 100644
--- a/app/V1Module/presenters/GroupsPresenter.php
+++ b/app/V1Module/presenters/GroupsPresenter.php
@@ -364,6 +364,10 @@ public function checkSetOrganizational(string $id)
         if (!$this->groupAcl->canSetOrganizational($group)) {
             throw new ForbiddenRequestException();
         }
+
+        if ($group->isExam()) {
+            throw new BadRequestException("Organizational group must not be exam group.");
+        }
     }
 
     /**
@@ -474,6 +478,10 @@ public function checkSetExam(string $id)
             throw new BadRequestException("Exam group must have no sub-groups.");
         }
 
+        if ($group->isOrganizational()) {
+            throw new BadRequestException("Exam group must not be organizational.");
+        }
+
         if (!$this->groupAcl->canSetExamFlag($group)) {
             throw new ForbiddenRequestException();
         }