I have multiple FCnn servers to play with, but limited bandwidth to download updates.
My solution was to on one machine change yum to keep the rpms it downloaded for updates in cache, and move the cached rpms to a local repository on served by that machine. Then use the yum priorities plugin on all my other servers to search that one machine on my local network for updates before searching the web.
This solution will still search the web for dependencies if needed, so nothing breaks this way.
There are lots of posts out there on how to create a local mirror of the updates repository, but I don't have the bandwidth for that, nor do most of us need every package in the updates repository.
This solution creates a local repository containing only the updates made to packages I am using, needing minimal disk space but still allowing all my other servers get updates for those same packages from the internal network.
Hopefully usefull to others.
The attachment is a pdf explaining how I set my environment up, created by openoffice, which is one of those updates I didn't want to pull down off the web for multiple servers :-), much better to serve the updates from the local network.