So, there is a website. It lists a number of products. They have no seperate detail pages, but instead all products of a certain category are shown in one list, with information about them, price, photo and so on. You can't buy them on that site though. If you want to buy one, you click on "buy" and are sent to another website, on a different domain, that holds the shop. There you see the same information of the product you are interested in, as it was seen in that list. Same text, same photo and so on.

Following questions:
- Does the google robot follow the link in a div containing the product information and reach a website with a nearly similiar div, and then recognizes that as copy and punishes the SEO rating?

- If that is the case, would a simple "no-follow" in the links sort that out, or are canonical links necessary?

- And, if no-follow wouldn't get the desired result and canonical links are necessary: there are sometimes dozens of such products in one list. I guess I'd need several dozen canonical links? But I read somewhere, that if there is more than one canonical link used in one header, that they are all ignored.

- And: at the time the header is loaded, I don't know yet how many items are in that list, since they're added by a PHP script. How to get the necessary canonical links into the header without knowing at that time what links are necessary?

Thanks for any advice.