apache2 - rewriting/proxying multiple services on a single ip

Question

I'm struggling with an apache2 configuration where I want to proxy or rewrite (or do both) to give access to services via port 80. I've managed it for single services, either with proxy or rewrite, but I lack experience to combine it into a working setup.

The idea is to do the following:

call:                    will be transformed to
www.example.com/         example.com:80/
cms.example.com/         example.com:8080:/
pad.example.com/         example.com:9000:/

some background: port 8080 goes to Plone, Port 9000 is etherpad. There is only one physical domain (one IP).

The reason to do it: some users are not allowed to use URLs with ports other then 80...

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As an alternative, the following mapping would be great too:

call:                    will be transformed to
example.com/     (*)     example.com:80/
example.com/cms/         example.com:8080:/
example.com/pad/         example.com:9000:/

(*) anything but /cms/* and /pad/*