diff --git a/mail-server.nix b/mail-server.nix
index 10b88b7..05abd36 100644
--- a/mail-server.nix
+++ b/mail-server.nix
@@ -136,19 +136,28 @@ in {
       };
     };
 
-    users.users = {
-      mailserver-dovecot = {
-        uid = 4455;
-        isSystemUser = true;
+    users = {
+      users = {
+        mailserver-dovecot = {
+          uid = 4455;
+          isSystemUser = true;
+          group = "mailserver-dovecot";
+        };
+        mailserver-antivirus = {
+          uid = 4456;
+          isSystemUser = true;
+          group = "mailserver-antivirus";
+        };
+        mailserver-dkim = {
+          uid = 4457;
+          isSystemUser = true;
+          group = "mailserver-dkim";
+        };
       };
-      mailserver-antivirus = {
-        uid = 4456;
-        isSystemUser = true;
-
-      };
-      mailserver-dkim = {
-        uid = 4457;
-        isSystemUser = true;
+      groups = {
+        mailserver-dovecot = { };
+        mailserver-antivirus = { };
+        mailserver-dkim = { };
       };
     };