about 'forward'

`var routes = {
	'/api': {
		'/:id': {
			'/:id': {
				on: f3
			},
			on: f2
		},
		on: f1
	}
};`

`var router = Router(routes).configure({ 
	recurse: 'forward'
});`

I want it to be f1-->f2-->f3
but  f1-->f3-->f2
