Fixed: [Issue 26] Add support for groups
https://code.google.com/p/protobuf-dt/issues/detail?id=26

com.google.eclipse.protobuf.ui/icons/group.gif

diff --git a/com.google.eclipse.protobuf.ui/icons/group.gif b/com.google.eclipse.protobuf.ui/icons/group.gif
new file mode 100644
index 0000000..0a13d8c
--- /dev/null
+++ b/com.google.eclipse.protobuf.ui/icons/group.gif
Binary files differ

com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/labeling/Images.java

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/labeling/Images.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/labeling/Images.java
index cabd71b..0534220 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/labeling/Images.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/labeling/Images.java
@@ -41,6 +41,7 @@
   static {
     IMAGES_BY_TYPE.put(Enum.class, "enum.gif");
     IMAGES_BY_TYPE.put(ExtendMessage.class, "extend.gif");
+    IMAGES_BY_TYPE.put(Group.class, "group.gif");
     IMAGES_BY_TYPE.put(Import.class, "import.gif");
     IMAGES_BY_TYPE.put(Literal.class, "literal.gif");
     IMAGES_BY_TYPE.put(Message.class, "message.gif");

com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext

diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
index c359ff3..fd6b46b 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
@@ -49,7 +49,12 @@
   '}'(';')?;
 
 MessageElement:
-  Type | Property;
+  Type | Property | Group;
+
+Group:
+  modifier=Modifier 'group' name=ID '=' index=INT '{'
+  elements+=Property*
+  '}';
 
 Property:
   modifier=Modifier type=AbstractTypeReference name=ID '=' index=INT (('[' 'default' '=' default=ValueRef