This subsetter first gets all of the successful stations for this events. Then it takes the current station, and if location falls within the distance variance of one of the already accepted stations, the event-station pair is rejected. This allows for the use of only one of several very similar stations for each event. Note that because this happens in the waveform arm, it is not guarantied that the same station will be used for each event. Also, if multiple waveformWorkerThreads are used, there is a small chance that more than one station for the same event will be processed.
In eventStation there is a choice between all of the following