Resources with deeply nested URLS do not necessarily contain the route parameters themselves, so cannot fill in all parameterised parts of the URL when PUTing/POSTing/DELETEing.
A new concept should be introduced such that when creating a new resource object, it is given its 'route params'. Similarly, in order to GET a resource the route params must be passed as arguments anyway - all we need to arrange is for the resource to remember them.