AMQNET-595: Set and get group-id message property field
diff --git a/src/NMS.AMQP/Message/Facade/INmsMessageFacade.cs b/src/NMS.AMQP/Message/Facade/INmsMessageFacade.cs
index 6520079..34bffd9 100644
--- a/src/NMS.AMQP/Message/Facade/INmsMessageFacade.cs
+++ b/src/NMS.AMQP/Message/Facade/INmsMessageFacade.cs
@@ -37,6 +37,7 @@
         DateTime NMSTimestamp { get; set; }
         string NMSType { get; set; }
         string GroupId { get; set; }
+        uint GroupSequence { get; set; }
         DateTime Expiration { get; set; }
         sbyte JmsMsgType { get; }
         INmsMessageFacade Copy();
diff --git a/src/NMS.AMQP/Message/NmsMessage.cs b/src/NMS.AMQP/Message/NmsMessage.cs
index d78b300..9f9c1c9 100644
--- a/src/NMS.AMQP/Message/NmsMessage.cs
+++ b/src/NMS.AMQP/Message/NmsMessage.cs
@@ -94,13 +94,19 @@
             get => Facade.NMSType;
             set => Facade.NMSType = value;
         }
-        
-        public string NMSGroupId
+
+        public string NMSXGroupId
         {
             get => Facade.GroupId;
             set => Facade.GroupId = value;
         }
 
+        public int NMSXGroupSeq
+        {
+            get => (int) Facade.GroupSequence;
+            set => Facade.GroupSequence = (uint) value;
+        }
+
         public NmsAcknowledgeCallback NmsAcknowledgeCallback { get; set; }
 
         public virtual bool IsReadOnly { get; set; }
diff --git a/test/Apache-NMS-AMQP-Test/Message/Facade/NmsTestMessageFacade.cs b/test/Apache-NMS-AMQP-Test/Message/Facade/NmsTestMessageFacade.cs
index 1ebbc6b..4f04440 100644
--- a/test/Apache-NMS-AMQP-Test/Message/Facade/NmsTestMessageFacade.cs
+++ b/test/Apache-NMS-AMQP-Test/Message/Facade/NmsTestMessageFacade.cs
@@ -74,6 +74,7 @@
         public DateTime NMSTimestamp { get; set; }
         public string NMSType { get; set; }
         public string GroupId { get; set; }
+        public uint GroupSequence { get; set; }
         public DateTime Expiration { get; set; }
         public sbyte JmsMsgType { get; }
         public INmsMessageFacade Copy()
diff --git a/test/Apache-NMS-AMQP-Test/Message/NmsMessageTest.cs b/test/Apache-NMS-AMQP-Test/Message/NmsMessageTest.cs
index 3256ccc..308bc53 100644
--- a/test/Apache-NMS-AMQP-Test/Message/NmsMessageTest.cs
+++ b/test/Apache-NMS-AMQP-Test/Message/NmsMessageTest.cs
@@ -401,11 +401,21 @@
         {
             NmsMessage msg = factory.CreateMessage();
             
-            msg.Properties.SetString("NMSGroupId", "testGroupId");
+            msg.Properties.SetString("NMSXGroupId", "testGroupId");
             
             Assert.AreEqual(msg.Facade.GroupId, "testGroupId");
         }
         
+        [Test]
+        public void TestSetAndGetGroupSequence()
+        {
+            NmsMessage msg = factory.CreateMessage();
+            
+            msg.Properties.SetInt("NMSXGroupSeq", 10);            
+            
+            Assert.AreEqual(msg.Facade.GroupSequence, 10);
+        }
+        
         // TODO: Test conversion for other properties
 
         [Test]