Returns True if the specified shape is a member of a group, False otherwise. Read-only Boolean.
expression.IsGroupMember
expression Required. An expression that returns one of the objects in the Applies To list.
The object returned by the ParentGroupShape property can be used to determine the parent shape for the group.
The following statement can be used to return a True value if the first shape of the active publication is a group member.
blnGrouped = Application.ActiveDocument.MasterPages _
.Item.Shapes(1).IsGroupMember