Set the identification for the instance group to modify. You can specify either
            core or task if there is only one instance group of that role. Otherwise you can
            specify the instance group ID (such as ig-ABABABABABAB).
            
 Declaration Syntax
 Declaration Syntax| C# | 
[ObsoleteAttribute("The With methods are obsolete and will be removed in version 2 of the AWS SDK for .NET. See http://aws.amazon.com/sdkfornet/#version2 for more information.")] public ModifyInstanceGroup WithInstanceGroup( string instanceGroup )
 Parameters
 Parameters- instanceGroup (String)
- Identifier for the instance group.
 Return Value
 Return ValueA reference to this updated object so that method calls can be chained
                    together.