diff --git a/src/main/java/mops/gruppen2/service/EventService.java b/src/main/java/mops/gruppen2/service/EventService.java
index 0c1e879..c28080c 100644
--- a/src/main/java/mops/gruppen2/service/EventService.java
+++ b/src/main/java/mops/gruppen2/service/EventService.java
@@ -6,6 +6,8 @@ import mops.gruppen2.domain.event.Event;
 import mops.gruppen2.repository.EventRepository;
 import org.springframework.stereotype.Service;
 
+import java.util.List;
+
 @Service
 public class EventService {
     private final SerializationService serializationService;
@@ -48,4 +50,18 @@ public class EventService {
         }
         return tmpId;
     }
+
+    public List<EventDTO> findAllEvents() {
+        return null;
+    }
+
+    public Event getEvent(EventDTO eventDTO) {
+        try {
+            return serializationService.deserializeEvent(eventDTO.getEvent_payload());
+        } catch (JsonProcessingException e) {
+            e.printStackTrace();
+        }
+
+        return null;
+    }
 }
diff --git a/src/main/java/mops/gruppen2/service/GroupService.java b/src/main/java/mops/gruppen2/service/GroupService.java
index dbf8abe..1bbb222 100644
--- a/src/main/java/mops/gruppen2/service/GroupService.java
+++ b/src/main/java/mops/gruppen2/service/GroupService.java
@@ -7,11 +7,19 @@ import mops.gruppen2.domain.event.CreateGroupEvent;
 import mops.gruppen2.domain.event.Event;
 import org.springframework.stereotype.Service;
 
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 
 @Service
 public class GroupService {
 
+    private final EventService eventService;
+
+    public GroupService(EventService eventService) {
+        this.eventService = eventService;
+    }
+
     /**
      * Konstruiert eine vollständige Gruppe aus Events, welche dieselbe Gruppe betreffen.
      *
@@ -46,4 +54,27 @@ public class GroupService {
         }
         return newGroup;
     }
+
+    public List<Group> projectEventList(Map<Long, Group> groupMap, List<Event> events) {
+        for (Event event : events) {
+            if (event instanceof CreateGroupEvent) {
+                groupMap.put(event.getGroup_id(), new Group());
+            }
+
+            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) {
+                e.printStackTrace();
+            }
+
+        }
+
+        return new ArrayList<>(groupMap.values());
+    }
 }