there actually is, the train stop priority feature does exactly what you want. This is also the example that was used for train stop priority initially, preventing trains from just moving around advanced products while ignoring basic ingredients. You're right, I'm actually working on a design that ...

An interrupt that is allowed to interrupt other interrupts completely clears temporary stop schedule. E.g. Have a refuel interrupt that can interrupt others, and an interrupt that has 2 stops. If the refuel interrupt becomes valid before the train leaves the first station, then upon starting the ref...