Originally Posted by
cestmoi123
If you search through Kayak, you can choose the connecting airports (or to exclude connecting airports).
This does work, although it will also hide connecting airports on the other legs (so if the second leg is JFK-ATL-GIG it won't show up even if the flight back to AMS avoids the US)
It's slightly more complicated, but you can use
ITA matrix to specify layover airports for specific legs. FWIW, the cheapest that came up was €837 on United nonstop/United via IAH/Swiss via ZRH on the return.