Type a part number or a description once, pick the kind of shop and the countries, and open the search on every shop in its own tab. The list of shops is maintained by hand; if a search opens on the wrong page, the shop changed its website.
Careful: the search opens one new tab for every selected shop, up to a few dozen at once. Do not overdo it; pick only the countries you need, and close the tabs when you are done.
Each link opens in a new tab. If your browser blocked the pop-ups, allow them for this site once, or open the links one by one.