diff --git a/apiserver/apiserver/api/serializers.py b/apiserver/apiserver/api/serializers.py
index 1d6ae4a..c3fb24d 100644
--- a/apiserver/apiserver/api/serializers.py
+++ b/apiserver/apiserver/api/serializers.py
@@ -231,6 +231,14 @@ class AdminMemberSerializer(MemberSerializer):
         ]
 
     def update(self, instance, validated_data):
+        if 'precix_cnc_cert_date' in validated_data:
+            changed = validated_data['precix_cnc_cert_date'] != instance.precix_cnc_cert_date
+            if changed:
+                if validated_data['precix_cnc_cert_date']:
+                    utils_ldap.add_to_group(instance, 'CNC-Precix-Users')
+                else:
+                    utils_ldap.remove_from_group(instance, 'CNC-Precix-Users')
+
         if 'rabbit_cert_date' in validated_data:
             changed = validated_data['rabbit_cert_date'] != instance.rabbit_cert_date
             if changed:
diff --git a/apiserver/apiserver/api/views.py b/apiserver/apiserver/api/views.py
index 531df08..6fd4300 100644
--- a/apiserver/apiserver/api/views.py
+++ b/apiserver/apiserver/api/views.py
@@ -265,7 +265,11 @@ class TrainingViewSet(Base, Retrieve, Create, Update):
         elif session.course.id == 428:
             member.precix_cnc_cert_date = utils.today_alberta_tz() if status == 'Attended' else None
 
-            # TODO: change group membership
+            if utils_ldap.is_configured():
+                if status == 'Attended':
+                    utils_ldap.add_to_group(member, 'CNC-Precix-Users')
+                else:
+                    utils_ldap.remove_from_group(member, 'CNC-Precix-Users')
         elif session.course.id == 247:
             member.rabbit_cert_date = utils.today_alberta_tz() if status == 'Attended' else None