diff --git a/src/main/java/mops/gruppen2/service/GroupService.java b/src/main/java/mops/gruppen2/service/GroupService.java
index c9ab19d..d12d49c 100644
--- a/src/main/java/mops/gruppen2/service/GroupService.java
+++ b/src/main/java/mops/gruppen2/service/GroupService.java
@@ -1,11 +1,7 @@
 package mops.gruppen2.service;
 
-import lombok.EqualsAndHashCode;
 import mops.gruppen2.domain.Exceptions.EventException;
-import mops.gruppen2.domain.Exceptions.GroupDoesNotExistException;
 import mops.gruppen2.domain.Group;
-import mops.gruppen2.domain.event.CreateGroupEvent;
-import mops.gruppen2.domain.event.DeleteGroupEvent;
 import mops.gruppen2.domain.event.Event;
 import org.springframework.stereotype.Service;
 
@@ -23,36 +19,23 @@ public class GroupService {
         this.eventService = eventService;
     }
 
-    public List<Group> projectEventList(Map<Long, Group> groupMap, List<Event> events) throws EventException {
+
+    public List<Group> projectEventList(List<Event> events) throws EventException {
+        Map<Long, Group> groupMap = new HashMap<>();
+
         for (Event event : events) {
-            if (event instanceof CreateGroupEvent) {
-                groupMap.put(event.getGroup_id(), new Group());
-            }
-            if (event instanceof DeleteGroupEvent) {
-                groupMap.remove(event.getGroup_id());
-            } else {
-                try {
-                    Group group = groupMap.get(event.getGroup_id());
-
-                    if (group == null) {
-                        throw new GroupDoesNotExistException("Gruppe " + event.getGroup_id() + " existiert nicht");
-                    }
-
-                    group.applyEvent(event);
-                } catch (EventException e) {
-                    if (e instanceof GroupDoesNotExistException) {
-                        throw e;
-                    }
-                    e.printStackTrace();
-                }
-            }
-
+            getOrCreateGroup(groupMap, event.getGroup_id()).applyEvent(event);
         }
 
         return new ArrayList<>(groupMap.values());
     }
 
-    public List<Group> projectEventList(List<Event> events) throws EventException {
-        return projectEventList(new HashMap<>(), events);
+    //
+    private Group getOrCreateGroup(Map<Long, Group> groups, long group_id) {
+        if (!groups.containsKey(group_id)) {
+            groups.put(group_id, new Group());
+        }
+
+        return groups.get(group_id);
     }
 }