You can create your own repository if you have os image.
Mount os image at some folder say /var/rhel-repo using
mount -o loop /path/to/os_image /var/rhel-repo
create repo file in /etc/yum.repos.d/customrepo as
[customrepo]
name=Custom Repository
baseurl=file:///var/customrepo
enabled=1
gpgcheck=0
save file.Then
yum clean all