Using transaction or stats to filter different parts of a query

Hi Experts! Im looking for a way to show where i get bookingresponses with the SAME (duplicate) platformid but different reactorids. Example: 2019/02/03 12:02:14.458 [server1] event="Received booking response" platformid=12345 reactorid=72E1X9785 2019/02/04 18:02:14.458 [server2] event="Received booking response" platformid=12345 reactorid=92D3X1865 I tried a mix of using dedup and transasction but cant seem to filter on having what i want left. Thanks in advance Paul