diff --git a/crates/caldav/src/principal/mod.rs b/crates/caldav/src/principal/mod.rs
index c533ed1..3bae264 100644
--- a/crates/caldav/src/principal/mod.rs
+++ b/crates/caldav/src/principal/mod.rs
@@ -2,7 +2,9 @@ use crate::Error;
 use rustical_dav::extensions::CommonPropertiesExtension;
 use rustical_dav::privileges::UserPrivilegeSet;
 use rustical_dav::resource::{PrincipalUri, Resource, ResourceName};
-use rustical_dav::xml::{Resourcetype, ResourcetypeInner, SupportedReportSet};
+use rustical_dav::xml::{
+    GroupMemberSet, GroupMembership, Resourcetype, ResourcetypeInner, SupportedReportSet,
+};
 use rustical_store::auth::User;
 
 mod service;
@@ -82,9 +84,9 @@ impl Resource for PrincipalResource {
                         ))
                     }
                     PrincipalPropName::AlternateUriSet => PrincipalProp::AlternateUriSet,
-                    PrincipalPropName::PrincipalCollectionSet => {
-                        PrincipalProp::PrincipalCollectionSet(puri.principal_collection().into())
-                    }
+                    // PrincipalPropName::PrincipalCollectionSet => {
+                    //     PrincipalProp::PrincipalCollectionSet(puri.principal_collection().into())
+                    // }
                     PrincipalPropName::SupportedReportSet => {
                         PrincipalProp::SupportedReportSet(SupportedReportSet::all())
                     }
diff --git a/crates/caldav/src/principal/prop.rs b/crates/caldav/src/principal/prop.rs
index 010ffec..56c1d9c 100644
--- a/crates/caldav/src/principal/prop.rs
+++ b/crates/caldav/src/principal/prop.rs
@@ -1,6 +1,6 @@
 use rustical_dav::{
     extensions::CommonPropertiesProp,
-    xml::{HrefElement, SupportedReportSet},
+    xml::{GroupMemberSet, GroupMembership, HrefElement, SupportedReportSet},
 };
 use rustical_store::auth::user::PrincipalType;
 use rustical_xml::{EnumVariants, PropName, XmlDeserialize, XmlSerialize};
@@ -24,8 +24,8 @@ pub enum PrincipalProp {
     GroupMemberSet(GroupMemberSet),
     #[xml(ns = "rustical_dav::namespace::NS_DAV", rename = b"alternate-URI-set")]
     AlternateUriSet,
-    #[xml(ns = "rustical_dav::namespace::NS_DAV")]
-    PrincipalCollectionSet(HrefElement),
+    // #[xml(ns = "rustical_dav::namespace::NS_DAV")]
+    // PrincipalCollectionSet(HrefElement),
     #[xml(ns = "rustical_dav::namespace::NS_DAV", skip_deserializing)]
     SupportedReportSet(SupportedReportSet<ReportMethod>),
 
@@ -41,12 +41,6 @@ pub enum PrincipalPropWrapper {
     Common(CommonPropertiesProp),
 }
 
-#[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
-pub struct GroupMembership(#[xml(ty = "untagged", flatten)] pub(super) Vec<HrefElement>);
-
-#[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
-pub struct GroupMemberSet(#[xml(ty = "untagged", flatten)] pub(super) Vec<HrefElement>);
-
 #[derive(XmlSerialize, PartialEq, Clone, VariantArray)]
 pub enum ReportMethod {
     // We don't actually support principal-match
diff --git a/crates/carddav/src/principal/mod.rs b/crates/carddav/src/principal/mod.rs
index 97c8398..0e8ec58 100644
--- a/crates/carddav/src/principal/mod.rs
+++ b/crates/carddav/src/principal/mod.rs
@@ -2,7 +2,9 @@ use crate::Error;
 use rustical_dav::extensions::CommonPropertiesExtension;
 use rustical_dav::privileges::UserPrivilegeSet;
 use rustical_dav::resource::{PrincipalUri, Resource, ResourceName};
-use rustical_dav::xml::{HrefElement, Resourcetype, ResourcetypeInner};
+use rustical_dav::xml::{
+    GroupMemberSet, GroupMembership, HrefElement, Resourcetype, ResourcetypeInner,
+};
 use rustical_store::auth::User;
 
 mod service;
@@ -13,6 +15,7 @@ pub use prop::*;
 #[derive(Debug, Clone)]
 pub struct PrincipalResource {
     principal: User,
+    members: Vec<String>,
 }
 
 impl ResourceName for PrincipalResource {
@@ -41,7 +44,7 @@ impl Resource for PrincipalResource {
         user: &User,
         prop: &PrincipalPropWrapperName,
     ) -> Result<Self::Prop, Self::Error> {
-        let principal_href = HrefElement::new(puri.principal_uri(&user.id));
+        let principal_href = HrefElement::new(puri.principal_uri(&self.principal.id));
 
         Ok(match prop {
             PrincipalPropWrapperName::Principal(prop) => {
@@ -60,6 +63,14 @@ impl Resource for PrincipalResource {
                                 .collect(),
                         ))
                     }
+                    PrincipalPropName::GroupMemberSet => {
+                        PrincipalProp::GroupMemberSet(GroupMemberSet(
+                            self.members
+                                .iter()
+                                .map(|principal| puri.principal_uri(principal).into())
+                                .collect(),
+                        ))
+                    }
                     PrincipalPropName::AlternateUriSet => PrincipalProp::AlternateUriSet,
                     PrincipalPropName::PrincipalCollectionSet => {
                         PrincipalProp::PrincipalCollectionSet(puri.principal_collection().into())
diff --git a/crates/carddav/src/principal/prop.rs b/crates/carddav/src/principal/prop.rs
index da7afc0..b1d83e5 100644
--- a/crates/carddav/src/principal/prop.rs
+++ b/crates/carddav/src/principal/prop.rs
@@ -1,4 +1,7 @@
-use rustical_dav::{extensions::CommonPropertiesProp, xml::HrefElement};
+use rustical_dav::{
+    extensions::CommonPropertiesProp,
+    xml::{GroupMemberSet, GroupMembership, HrefElement},
+};
 use rustical_xml::{EnumVariants, PropName, XmlDeserialize, XmlSerialize};
 
 #[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone, EnumVariants, PropName)]
@@ -10,6 +13,8 @@ pub enum PrincipalProp {
     PrincipalUrl(HrefElement),
     #[xml(ns = "rustical_dav::namespace::NS_DAV")]
     GroupMembership(GroupMembership),
+    #[xml(ns = "rustical_dav::namespace::NS_DAV")]
+    GroupMemberSet(GroupMemberSet),
     #[xml(ns = "rustical_dav::namespace::NS_DAV", rename = b"alternate-URI-set")]
     AlternateUriSet,
     #[xml(ns = "rustical_dav::namespace::NS_DAV")]
@@ -28,6 +33,3 @@ pub enum PrincipalPropWrapper {
     Principal(PrincipalProp),
     Common(CommonPropertiesProp),
 }
-
-#[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
-pub struct GroupMembership(#[xml(ty = "untagged", flatten)] pub(super) Vec<HrefElement>);
diff --git a/crates/carddav/src/principal/service.rs b/crates/carddav/src/principal/service.rs
index 5edd65f..d607f0f 100644
--- a/crates/carddav/src/principal/service.rs
+++ b/crates/carddav/src/principal/service.rs
@@ -65,7 +65,10 @@ impl<A: AddressbookStore, AP: AuthenticationProvider, S: SubscriptionStore> Reso
             .get_principal(principal)
             .await?
             .ok_or(crate::Error::NotFound)?;
-        Ok(PrincipalResource { principal: user })
+        Ok(PrincipalResource {
+            members: self.auth_provider.list_members(&user.id).await?,
+            principal: user,
+        })
     }
 
     async fn get_members(
diff --git a/crates/dav/src/xml/group.rs b/crates/dav/src/xml/group.rs
new file mode 100644
index 0000000..fe54805
--- /dev/null
+++ b/crates/dav/src/xml/group.rs
@@ -0,0 +1,8 @@
+use crate::xml::HrefElement;
+use rustical_xml::{XmlDeserialize, XmlSerialize};
+
+#[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
+pub struct GroupMembership(#[xml(ty = "untagged", flatten)] pub Vec<HrefElement>);
+
+#[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
+pub struct GroupMemberSet(#[xml(ty = "untagged", flatten)] pub Vec<HrefElement>);
diff --git a/crates/dav/src/xml/mod.rs b/crates/dav/src/xml/mod.rs
index 2c0f454..beac1f5 100644
--- a/crates/dav/src/xml/mod.rs
+++ b/crates/dav/src/xml/mod.rs
@@ -13,3 +13,5 @@ pub mod sync_collection;
 pub use error::ErrorElement;
 mod report_set;
 pub use report_set::SupportedReportSet;
+mod group;
+pub use group::*;