Context
The difference between a product is and what an offer is, should be clear to you, but if you need more information regarding this topic please consult:this article.
This article introduces a different concept and explains how pricing ties into products and offers.
Please find the outline of the difference between a product file, an offer file and a price file:
How does this relate to PPCG segmentation?
It links to the Price Per Customer Group Segmentation as this feature will allow you to link different prices & offers aimed at different customers groups, for the same product.
I.e. You can offer a price of 10EUR for champagne for Hotel X but offer a price of 12 EUR for champagne for Hotel Y.
Please note! Should you have the need to manage multiple prices for different customer groups, you can not use the offer file but should always use the prices instead.