diff --git a/appinfo/routes.php b/appinfo/routes.php
index 98812d6..21f9ef7 100644
--- a/appinfo/routes.php
+++ b/appinfo/routes.php
@@ -9,7 +9,7 @@ return [
        ['name' => 'agency#show', 'url' => '/getagencydata', 'verb' => 'GET'],
        ['name' => 'agency#updateagencydata', 'url' => '/updateagencydata', 'verb' => 'PUT'],
        ['name' => 'agency#getagencycontributors', 'url' => '/getagencycontributors', 'verb' => 'GET'],
-       ['name' => 'agency#updateagencygroupcontributors', 'url' => '/updateagencygroupcontributors/{gid}', 'verb' => 'POST'],
+       ['name' => 'agency#updateagencygroupcontributors', 'url' => '/updateagencygroupcontributors/{gid}', 'verb' => 'PUT'],
        # GROUPS
        ['name' => 'group#getagencygroups', 'url' => '/getagencygroups', 'verb' => 'GET'],
        ['name' => 'group#addagencygroup', 'url' => '/addagencygroup', 'verb' => 'PUT'],
diff --git a/lib/Agency/AgencyManager.php b/lib/Agency/AgencyManager.php
index 520658e..652de31 100644
--- a/lib/Agency/AgencyManager.php
+++ b/lib/Agency/AgencyManager.php
@@ -3,6 +3,7 @@ namespace OCA\Agency\Agency;
 
 use OCP\IRequest;
 use OCP\IUserSession;
+use OCP\IUserManager;
 use OCP\IDBConnection;
 use OCA\Agency\Db\AgencyMapper;
 use OCA\Agency\Service\AgencyService;
@@ -14,12 +15,14 @@ class AgencyManager {
     protected $agencyMapper;
     protected $groupManager;
     protected $userSession;
+    protected $userManager;
     protected $db;
 
-    public function __construct($AppName, IDBConnection $db, IRequest $request, AgencyMapper $agencyMapper, IGroupManager $groupManager, IUserSession $userSession) {
+    public function __construct($AppName, IDBConnection $db, IRequest $request, AgencyMapper $agencyMapper, IGroupManager $groupManager, IUserSession $userSession, IUserManager $userManager) {
         $this->agencyMapper = $agencyMapper;
         $this->groupManager = $groupManager;
         $this->userSession = $userSession;
+        $this->userManager = $userManager;
 	}
     /**
      * Creates a new Agency and save it to the database.
@@ -94,4 +97,24 @@ class AgencyManager {
 		}
         return $return_users;
     }
+
+    # TODO: Hier prüfen, ob alle User in der gleichen Agentur sind und er eingeloggte User auch wirklich das Recht dazu hat
+    public function updateagencygroupcontributors(string $gid, array $users){
+        $groupToChange = $this->groupManager->get($gid); 
+        $usersInGroup = $groupToChange->getUsers();
+
+        foreach($usersInGroup as $user){
+            if($groupToChange->canRemoveUser()){
+                $groupToChange->removeUser($user);
+            }
+        }
+
+        foreach($users as $user) {
+            if($groupToChange->canAddUser()){
+                $groupToChange->addUser($this->userManager->get($user));
+            }
+        }
+        return $users;
+    }
+
 }
\ No newline at end of file
diff --git a/lib/Controller/AgencyController.php b/lib/Controller/AgencyController.php
index 5c18a8f..6626dc2 100644
--- a/lib/Controller/AgencyController.php
+++ b/lib/Controller/AgencyController.php
@@ -5,6 +5,7 @@ namespace OCA\Agency\Controller;
 
 use OCP\IRequest;
 use OCP\IUserSession;
+use OCP\IUserManager;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\AppFramework\Http\JSONResponse;
 use OCP\AppFramework\Controller;
@@ -15,7 +16,6 @@ use OCP\IDBConnection;
 
 class AgencyController extends Controller {
 
-    protected $userManager;
     private $service;
     private $Id;
     protected $userSession;
@@ -109,8 +109,8 @@ class AgencyController extends Controller {
      * 
      */
     # TODO: Noch prüfen, OB der Nutzer das überhautp darf und Agenturcheck usw.
-    public function updateagencygroupcontributors(string $gid){
-        return $_POST;
+    public function updateagencygroupcontributors(string $gid, array $users){
+        return $this->agencyManager->updateagencygroupcontributors($gid, $users);
     }
 
 }
\ No newline at end of file
diff --git a/lib/Controller/GroupController.php b/lib/Controller/GroupController.php
index bf9b772..60cdeb0 100644
--- a/lib/Controller/GroupController.php
+++ b/lib/Controller/GroupController.php
@@ -54,12 +54,19 @@ class GroupController extends Controller {
             if(str_contains($group->getGId(), 'subgroup')){
                 $isDefault = false;
             }
+
+            //Checking if the Group is the Main-Group - EVERY User of this Agency should be in this group!
+            $isMainGroup = false;
+            if(sizeof(explode("_", strval($group->getGId()))) == 2){
+                $isMainGroup = true;
+            }
+
             // Adding current Users to the Group
             $user_groups = [];
             foreach($group->getUsers() as $groupuser){
                 array_push($user_groups, array("user" => $groupuser->getUID(), "displayName" => $groupuser->getDisplayName()));
             }
-            array_push($response_groups, array('name' => $group->getDisplayName(), 'gid' => $group->getGid(), 'isDefault' => $isDefault, 'users' => $user_groups));
+            array_push($response_groups, array('name' => $group->getDisplayName(), 'gid' => $group->getGid(), 'isDefault' => $isDefault, 'isMainGroup' => $isMainGroup, 'users' => $user_groups));
         }
         //Sorting the Array A-Z by GroupDisplayName
         $keys = array_column($response_groups, 'name');
diff --git a/src/components/Group.vue b/src/components/Group.vue
index 0abbb71..7044f9a 100644
--- a/src/components/Group.vue
+++ b/src/components/Group.vue
@@ -32,13 +32,13 @@
 					placeholder="Suche"
 					:options="agencyContributor"
 					@input="updateContributor" />-->
-				<Multiselect v-model="value"
+				<Multiselect v-if="!group.isMainGroup"
+					v-model="value"
 					:options="formattedContributors"
 					label="displayName"
 					placeholder="Mitarbeiter der Gruppe hinzufügen"
 					track-by="user"
 					:multiple="true"
-					:user-select="true"
 					style="width: 350px"
 					@input="updateContributorsValue()">
 					<template #singleLabel="{ option }">
@@ -87,15 +87,16 @@ export default {
 		}
 	},
 	mounted() {
+		this.value = null
 		this.getAgencyContributors()
 	},
 	methods: {
 		async updateContributorsValue() {
-			let valueData = ''
+			const selectedUsers = []
 			this.value.forEach((item) => {
-				valueData += item.user + '___'
+				selectedUsers.push(item.user)
 			})
-			const r = await axios.post(generateUrl('/apps/agency/updateagencygroupcontributors/' + this.group.gid), valueData)
+			const r = await axios.put(generateUrl('/apps/agency/updateagencygroupcontributors/' + this.group.gid), { users: selectedUsers })
 			console.log(r)
 		},
 		// Contributors changed, update the formattedContributors for the Field