I would like to take a cheap day trip to another country. The destination does not matter but the route must go through Antwerp’s south station. I need to hop off there for a visit before continuing on.

I recall an EU rule that if a train ticket crosses a national border, then passengers have an automatic right to get off the train at any stop along the way and hang out before continuing on the same route with another train.

Of course I can buy a ticket to Antwerp South and then buy a separate ticket elsewhere, like Rotterdam for example. But that costs more. In principle it should be possible to specify origin and a “via” waypoint, and not specify the ultimate destination. I want to be told what destinations naturally happen to traverse Antwerp South.

Are there any search tools that can handle this?