Rails - May 2009 - Executing multiple controllers with one request

I''m designing an Ajax RPC Router for Rails using Ext JS library.

I need to dispatch actions to multiple controllers during a single
request.

I made a piece of Rack Middleware and plugged it in to Rails
initializer in environment.rb

<code>
Rails::Initializer.run do |config|
    config.middleware.use MyRouter "rpc"
end
</code>

The following Rack Middleware is *far* from being complete.  I show
dispatching to hard-coded controller/actions here as an example.

<code>
class MyRouter
  def initialize(app, rpc_path)
    @app = app
    @rpc_path = rpc_path
  end

  def call(env)
    request_env = env.dup  // <-- have to duplicate env for each
request
    if request_env["PATH_INFO"].match("^"+@rpc_path)  #
<-- detect rpc
path
      output = [] # <-- capture each controller''s response into an
array
      ["company", "user"].each do |controller_name|
        request_env["PATH_INFO"] =
"/#{controller_name}/load"  # <--
re-write env
        request_env["REQUEST_URI"] =
"/#{controller_name}/load"
        output << @app.call(request_env)  # <-- Is it kosher to call
multiple controllers like this??
      end
      [200, {"Content-Type" => "text/html"},
process_response(output)]
    else
      @app.call(env)
    end
  end

  def process_response(list)
      # iterate array of controller responses and return the body from
each.
  end
end
</code>

Is it OK to dispatch to multiple controllers like this?
In Merb, I implemented this RPC functionality using merb-parts.
Is there a similar/better way in Rails?