[CentOS] Naming packages in custom yum repo.

I need to setup a custom yum repo to supply some packages that are not
in CentOS, and some that are but have been patched and/or are
different versions.  Not much of a big deal.

In order to limit conflict with CentOS packages, I am using a prefix
other than /usr.  All my packages that also have existing versions in
CentOS are installed under this new prefix to prevent any conflict
with the CentOS package.  My main issue is I would like yum (and rpm)
to be happy with this coexistence.

Is the only way to do this by giving my packages a different name
rather than just twiddling the release number?

For example, CentOS has libpcap-0.8.3, I need to supply a patched
libpcap-0.8.4 but I don't want it to replace the 0.8.3 package, so
I've modified the package name to be like <something>.libpcap-0.8.3...

I know this may same weird, but is prefixing the package name a sane
approach to this?

On a related note, I also supply a modified kernel and I don't want
yum to replace the kernel when its updated on a CentOS mirror.  Is the
best way to do this with a the ignore option in the yum repo
configuration?

Thanks,
Jason