Serving multiple Rails apps from single domain

I have two Rails apps that I want to serve with Passenger from the same domain.

I would like requests to come in to one app, and if that app is not able to handle the request, for the request to be 开发者_Go百科passed to the the second app.

I know that I can use Passenger's RailsBaseURI option to deploy multiple apps to different sub URIs, but this doesn't give the behaviour I'm after.

Is there a standard way to achieve this?

Thanks in advance, etc etc.

I think you can use haproxy as a load balancer.