All questions regarding mapmaking for Heroes of Might and Magic 3: The Shadow of Death.

I'm creating a map in the HotA 1.6.1 editor. The idea is to create an event that appears ONCE for EACH player when their hero steps onto a specific tile. The hero should fight once, receive spells, and that's it – the event is complete for them. However, the guarding creatures should remain in place, so that when another player activates the event, they also face the same creatures. Is this possible? If so, how can I achieve this?