Install the createrepo package:
http://dag.wieers.com/rpm/FAQ.php#B
http://dag.wieers.com/rpm/packages/createrepo/
yum install createrepo
rpm -ivh createrepo*.rpm
Create a local directory (lets say RHELupdates) that has the updates and place all the updates in that directory then use createrepo from that directory;
cd RHELupdates
createrepo RHELupdates
Copy the contents of the dirctory to the media and use a local.repo file located in the /etc/yum.repos.d directory which looks something like;
[rhelupdates]
name=Red Hat-$releasever - Media
baseurl=file:///media/cdrecorder
gpgcheck=0
enabled=0
Mount the media and as root do something like; yum update --enablerepo=rhelupdates