[Yum] question on yum.conf

[Nielsen, Steve]

I have my yum repository setup as follows:

distro/
  RedHat/   (all Redhat 7.3 RPMS with updates merged in)
  internal/ (rpms created internally or downloaded from 3rdparty)
  headers/  (yum headers)

I want to maintain a test area as well i.e.:

distro.test/
   updates/rh/ (nighly rsynced redhat updates (before merging))
   internal/   (internal new ones before merging)
   headers/    (yum headers)

I use yum 1.03 (because of redhat 7.3).

My question is can I configure yum.conf to hold both areas:

[distro]
...
[newstuff]
...

And tell it via command line to run against "distro" (normal stable stuff).
Then if I want to test upgrade a machine tell it to go against "newstuff" ?
Or do I have to have different config files and switch among them via the -c command
line switch ?

Basically what I am after is by default having machiens update against the golden
archive and a few machines update against the new RPMs so I can test before
pushing to my golden area.

Thanks,
Steve