Of course, create them with the same file structure that you mentioned above. In the same API folder, you can have multiple: controllers, models, services files. But a single routes file.
Take a look at the CLI commands documentation. There is shown how to create controllers/services/models inside another API.
/* First create the v1 API: */
yarn strapi generate:api v1
/* Then create others controllers/models/services inside it by using --api attribute. */
yarn strapi generate:controller countries --api v1
yarn strapi generate:model countries --api v1
yarn strapi generate:service countries --api v1
@jpizzle34 It is hardly to understand why this command is not working. For me I found a work-around to generate a single type by using the common api-generate command and manually file editing like this:
run strapi generate:api <yourapi-typename> <attributes-to-add>(attributes are optional)
if this was successful edit .settings.json and there add after the first curly bracket the line: "kind": "singleType",
now it is defined as singleType in Strapi, but the not neccessary endpoints have to be removed, so that the server can restart So go to the routes.json which refers to your new type and remove all routes except the GET, PUT and DELETE ones.
the single type should be shown from now on in admin-page. If not done by the generate command above, add new attributes to the new type with help of the content-type builder and also set permissions.