The basic steps and info...

1. Replicate the OSS (and any other repo) to a location you manage, likely in your local network. There are probably plenty of options how to do this, rsync is probably recommended most often but most likely because it enables you to easily update your copy should the source change which would not be the case with the OSS. Since the OSS doesn't change... You can simply use the DVD which is not exactly the same but pretty close and may be sufficient. You can do a regular "cp -r" but for something this large it's anyone's guess how well it will work. I expect you could probably use any cloning tool, too.,,, I haven't tried using dd in this kind of job, but it might work. The problem with dd though is that there is no built in error checking and correction so for a very big job like this over a long distance, you'd be relying on TCP only (in the TCP/IP) which might not be sufficient. Rsync might be a bit of overkill but still be the best tool that ensures a successful result.

2. Once you have a copy of the repo, you can set up your repo a number of different ways. If you copied the repo metadata with your repo, I'd expect that it should be all set up to be served as a yum type of repo (or whatever type, the yum format was used a long time ago when I did this). But zypper is very flexible and will support simple file and by extension likely network paths so you really do have maximum flexibility, even without a server for setting up and pointing to your repo. In other words, you don't have to set up a web or ftp server like what is done with public repos.

3. Disable or remove the default repo entry that points to the default OSS, and create a new repo with path to your local repo.

I don't think I'm missing any steps, and I hope the additional info I provided you is enough for you to set up successfully.