[CentOS] Allow updates but not upgrades

Thu May 10 05:36:07 UTC 2012
Gregory Machin <gdm at linuxpro.co.za>

At the moment it seems my machines just update to the latest current
release . I install a 6.0 machine and run yum update , and next thing
its 6.2 .

I have a requirement where I need machines to only upgrade to even
numbered sub releases eg: 6.0 , 6.2, 6.4 and only on my approval. But
will allow updates within a given release.

How can I achieve this ?

If I sync the repositories for eg: 6.0 , 6.2, 6.4 separately in
Spacewalk and only allow access to the ones I want to give access to,
would that work ?