I think ideally, it's just about having the right language in the agreements. The Orange Bowl and ACC could agree to a deal where ND is part of it, but still relies on an invite in a given year. So it's about signing up ND so that WHEN the Orange Bowl WANTS ND, ND is locked in. If it means HAVING to put them in the rotation once every 5 years if they finish with 2 or less losses to get them signed up, it's probably worth it.
That can be sort of tricky, though, when it plays out. Many bowls would want Notre Dame regardless of their record because of the money they generate and how well the school and fans travel. I think the OB would want them just about every year, then. But when the Irish are REALLY good, I suspect the OB won't get them. Assuming ND keeps the most-favored-indie status, if ND breaks the top 10, they're a playoff team.
When Notre Dame won't be good enough for a playoff, and find themselves in the OB, we'll see the variations of the '06 Fiesta and '07 Sugar; an overrated paper giant exposed by an actual and true good team. That will get old very fast to the ACC and its fans.