@danyj This isn’t something that GitHub offers as a feature at this time. It’s something that you *might* be able to implement with a lot of API work, which is something you might have more help with over on the Platform Forum. That said, there are a lot of potential complications with this. Two of the big ones that come to mind are: 

• Every customer you have would have to have a GitHub account already in order to access and use that private repository
• If the private repository you’re trying to direct them to exists in an organization account, you’d end up paying for a seat every time a customer got access to that private repository

All in all, I think this is a really great idea, but it’s not something that exists out-of-the-box on github.com right now. I will, however, note it in our internal feature request list. Though I can’t guarantee anything or share a timeline for if or when this might be implemented, I can tell you that it’s been shared with the appropriate teams for consideration.