ExpertThere are a few ways you could accomplish this. A datasource would definitely do it, but depending on the data it might not work as well as you’d like.
Another option would be to use the collector script cache to keep track of the events that were already picked up by the eventsource. If the event has some sort of unique identifier, or a string of text that could uniquely identify it, you could store that in a list in the collector script cache. Then when the eventsource runs, it would still fetch the event even though it fetched it previously. But before outputting the event to LM, it could check if the event is in the script cache. If it is, it could skip outputting that event and not open another event.