Does the RR-OS work if I have more than one core offer?

YES, for sure!

We have experience using this system to guide people into multiple back-end offers, and many of our clients are implementing it that way too. 

When you release your Gateway Products, you can alternate between which of your back-end offers you’re introducing (based on topical relevancy and your sales goals). Or, you can present people with multiple upgrade options if both/all of your back-end offers make sense after they buy one of your Gateway products.