How to organize networking between web server and many web applications in Docker?

We have a server with one IP-address and we plan to run approx. 30 web applications on that server each inside a Docker container.

To make those application accessible from outside we intend to run a webserver-container (i.e. Apache HTTPD) on this machine listening to 80/443, and configured with virtual hosts that proxy to our web applications.

How to organize networking between the webserver-container and application-containers in the light of Docker v1.9 with its new networking feature?