diff --git a/tiramisu/option/usernameoption.py b/tiramisu/option/usernameoption.py
index 4da7d97..02e98c8 100644
--- a/tiramisu/option/usernameoption.py
+++ b/tiramisu/option/usernameoption.py
@@ -29,4 +29,10 @@ class UsernameOption(RegexpOption):
     #regexp build with 'man 8 adduser' informations
     _regexp = re.compile(r"^[a-z_][a-z0-9_-]{0,30}[$a-z0-9_-]{0,1}$")
     _type = 'username'
-    _display_name = _('username')
+    _display_name = _('unix username')
+
+
+class GroupnameOption(UsernameOption):
+    __slots__ = tuple()
+    _type = 'groupname'
+    _display_name = _('unix groupname')