diff --git a/quickfix/src/message.rs b/quickfix/src/message.rs
index 40c5a95..99c5540 100644
--- a/quickfix/src/message.rs
+++ b/quickfix/src/message.rs
@@ -120,35 +120,33 @@ impl Message {
     }
 
     /// Clone struct group part for a given tag and group index.
-    pub fn clone_group(&self, index: i32, tag: i32) -> Result<Group, QuickFixError> {
-        unsafe { FixMessage_copyGroup(self.0, index, tag) }
-            .map(Group)
-            .ok_or(QuickFixError::NullFunctionReturn)
+    pub fn clone_group(&self, index: i32, tag: i32) -> Option<Group> {
+        unsafe { FixMessage_copyGroup(self.0, index, tag) }.map(Group)
     }
 
     /// Read struct group part for a given tag and group index.
-    pub fn with_group<T, F>(&self, index: i32, tag: i32, f: F) -> Result<T, QuickFixError>
+    pub fn with_group<T, F>(&self, index: i32, tag: i32, f: F) -> Option<T>
     where
         F: FnOnce(&Group) -> T,
     {
         if let Some(ptr) = unsafe { FixMessage_getGroupRef(self.0, index, tag) } {
             let obj = ManuallyDrop::new(Group(ptr));
-            Ok(f(&obj))
+            Some(f(&obj))
         } else {
-            Err(QuickFixError::NullFunctionReturn)
+            None
         }
     }
 
     /// Read or write struct group part for a given tag and group index.
-    pub fn with_group_mut<T, F>(&mut self, index: i32, tag: i32, f: F) -> Result<T, QuickFixError>
+    pub fn with_group_mut<T, F>(&mut self, index: i32, tag: i32, f: F) -> Option<T>
     where
         F: FnOnce(&mut Group) -> T,
     {
         if let Some(ptr) = unsafe { FixMessage_getGroupRef(self.0, index, tag) } {
             let mut obj = ManuallyDrop::new(Group(ptr));
-            Ok(f(&mut obj))
+            Some(f(&mut obj))
         } else {
-            Err(QuickFixError::NullFunctionReturn)
+            None
         }
     }
 }
diff --git a/quickfix/tests/test_message_group.rs b/quickfix/tests/test_message_group.rs
index 68e443c..90391e5 100644
--- a/quickfix/tests/test_message_group.rs
+++ b/quickfix/tests/test_message_group.rs
@@ -1,4 +1,5 @@
 use msg_const::*;
+use quickfix::*;
 
 mod msg_const;
 
@@ -24,3 +25,95 @@ fn test_build_with_group() {
          148=New great project available\u{1}10=205\u{1}"
     );
 }
+
+#[test]
+fn test_read_group_clone() {
+    let msg = build_news("Great news", &["Some new library", "are available", "soon"]).unwrap();
+    assert_eq!(msg.get_field(MSG_HEADLINE).unwrap(), "Great news");
+
+    // Read before
+    assert!(msg.clone_group(0, MSG_NO_LINES_OF_TEXT).is_none());
+
+    // Read configured lines
+    let group = msg.clone_group(1, MSG_NO_LINES_OF_TEXT).unwrap();
+    assert_eq!(group.get_field(MSG_TEXT).unwrap(), "Some new library");
+
+    let group = msg.clone_group(2, MSG_NO_LINES_OF_TEXT).unwrap();
+    assert_eq!(group.get_field(MSG_TEXT).unwrap(), "are available");
+
+    let group = msg.clone_group(3, MSG_NO_LINES_OF_TEXT).unwrap();
+    assert_eq!(group.get_field(MSG_TEXT).unwrap(), "soon");
+
+    // Read after
+    assert!(msg.clone_group(4, MSG_NO_LINES_OF_TEXT).is_none());
+}
+
+#[test]
+fn test_read_group_ref() {
+    let msg = build_news("Great news", &["Some new library", "are available", "soon"]).unwrap();
+    assert_eq!(msg.get_field(MSG_HEADLINE).unwrap(), "Great news");
+
+    fn read_text(group: &Group) -> String {
+        group.get_field(MSG_TEXT).unwrap()
+    }
+
+    // Read before
+    assert!(msg.with_group(0, MSG_NO_LINES_OF_TEXT, read_text).is_none());
+
+    // Read configured lines
+    assert_eq!(
+        msg.with_group(1, MSG_NO_LINES_OF_TEXT, read_text).unwrap(),
+        "Some new library"
+    );
+    assert_eq!(
+        msg.with_group(2, MSG_NO_LINES_OF_TEXT, read_text).unwrap(),
+        "are available"
+    );
+    assert_eq!(
+        msg.with_group(3, MSG_NO_LINES_OF_TEXT, read_text).unwrap(),
+        "soon"
+    );
+
+    // Read after
+    assert!(msg.with_group(4, MSG_NO_LINES_OF_TEXT, read_text).is_none());
+}
+
+#[test]
+fn test_modify_group() {
+    let mut msg = build_news("Great news", &["Some new library", "are available", "soon"]).unwrap();
+
+    // Check before
+    assert_eq!(
+        msg.as_string().unwrap(),
+        "9=70\u{1}35=B\u{1}33=3\u{1}\
+         58=Some new library\u{1}\
+         58=are available\u{1}\
+         58=soon\u{1}\
+         148=Great news\u{1}\
+         10=020\u{1}"
+    );
+
+    // Update valid group
+    assert!(msg
+        .with_group_mut(2, MSG_NO_LINES_OF_TEXT, |g| g
+            .set_field(MSG_TEXT, "will be available")
+            .unwrap())
+        .is_some());
+
+    // Update invalid group
+    assert!(msg
+        .with_group_mut(58, MSG_NO_LINES_OF_TEXT, |g| g
+            .set_field(MSG_TEXT, "whatever")
+            .unwrap())
+        .is_none());
+
+    // Check after
+    assert_eq!(
+        msg.as_string().unwrap(),
+        "9=74\u{1}35=B\u{1}33=3\u{1}\
+         58=Some new library\u{1}\
+         58=will be available\u{1}\
+         58=soon\u{1}148=Great news\u{1}\
+         10=127\u{1}"
+    );
+}