Calling RESTful 'scoped' INDEX when params[] is not present?

I have a VERY hierchical database and am using a RESTful approach. Normally, when users' enter the system they'll cascade from level to level in the database and thus the hierchical information such as child.parent.grandchild_id are always available to the RESTful routes. However, when I attempt to directly call a middle level table.index I obviously fail, because the parent_id is not available to pass to the RESTful route. I'd like to have a 'safety mechanism' built into my code that handles this by simple displaying all records irrespective of     Here is an example of my before_filter event and the way I use it to call my index:

def find_parent @find_parent || @project = Project.find(params[:project_id]) end

Here is a typical table.index action:

def index   @portals = @project.portals.find :all

Would it be possible to make the INDEX code something like this;

def index if @project.nil?   @portals = Portal.find :all else   @portals = @project.portals.find :all, end

    Fundumentally, what 'blows my mind' is that the 'find_parent' 'before_filter' event ALWAYS has to fire and if no parent exists, I can't see how to return a '...@project.nil' or whatever is needed to feed the if, else routine (above)?

Thank you, Kathy