You can't make subgroups in an application.
There are 3-4 subgroups already:
- Approved (this are the base sheets)
- Community (?) - the shared sheets
- Personal (?) - user created sheets, but not published
You can change the order of sheets to desired, while the application is in work stream.
You can organize the order simply with drag and drop.
If your application has been published, then duplicate it, rearrange the order and publish again with overwrite the old one.