How to make sub commands without the multi-word command feature?

The docs aren't too clear. Maybe it doesn't exist.

I know about multi-word commands, https://github.com/dthree/vorpal/wiki/api-%7C-vorpal.command#multi-word-commands.

But what I'm wondering about is something more along the lines of describing commands with nested functions, or with file hierarchy.

This is the feature in Yargs:

- example with folder hierarchy: https://github.com/yargs/yargs/blob/master/docs/advanced.md#example-command-hierarchy-using-commanddir
- example with nested functions: https://github.com/yargs/yargs/issues/225#issuecomment-128532719

Is multi-word the only way in Vorpal?