How to set multisites: same domain, different path, one ip address

[Jiongliang Zhang <zhnzhong521@xxxxxxxxx>]

I have implement something like this:

<virtualhost :80>
    mailman is here, 
</virtualhost>

<virtualhost :8080>
    redmine is here.
</virtualhost>

so when I using mydomain:80 and mydomain:8080, I can request both of them.
But now I have new reqirements, I hope using mydomain/mailman and mydomain/redmine
to identify them, just like:

    http://mydomain/mailman
    http://mydomain/redmine

on ubuntu server 8.04, apache2.2, ip: 192.168.1.128, domain: mydomain


mailman path:  /var/lib/mailman/*
redmine path: /var/lib/redmine/*

How can I do this. (I'm newbee on apache)

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Best regards！
Thanks
Jiongliang Zhang