Not really simple, honestly, especially if by "scenario searches" you mean "retrieving a list of results deduplicated by scenario" - as it is the same as that middleware thing. Only this would be embedded in ResultsDB, and that one would be a separate thing (which is good, btw, and as long as there is no rigorous specification, I'm not willing to put that stuff directly in resultsdb, as it would only cause more trouble than gain in the end).