Currently, My AutoSupport inherits the group feature of installed base available by navigating to the section below on NetApp Support site.
Home >> My Support >> Systems >> View Installed Systems
Once there, you can search for a system, and click the “Go” button to “Manage Product Location & Details” of a certain system.
In the next screen, click “Update Product Details” and you will get a text field to enter the group name.
You can find more details about the Group feature at http://now.netapp.com/NOW/knowledge/docs/help/groups_help.shtml
This feature is currently set at individual system level and process can be time consuming if there are several systems that need to be part of a group.
We are investigating possibilities to provide an easier & faster way to create custom group of systems in future in the manner you described within My AutoSupport.
Thanks,
Sudip