When I first read the Open Graph description in the post above:
"Overloading Google Search with relevant results from four sites at once, so you're more likely to get your answer", I thought it was intended to be a sarcastic remark... but apparently it is what Google is doing.
This feels analogous to what Google did over ten years back when, in the regular serps, Google offered multiple results (up to 4) from popular sites when the algorithm deemed that the best choices might be lost if results were limited to only one or two results per "host". It was initially called "brand authority" in the forums... and eventually also called "domain crowding".
When Google gathered enough data from this particular type of sorting, and it often took quite a bit of time, the results usually did get narrowed down to one or two results per domain.
I remember on one very infrequently searched product, though, it took over a year for results from one search I monitored for the top ranking site to get narrowed down from four pages to one page.
As I review some old discussions, this seems to be very similar... but simply in a different area in the serps. Here's one of the first threads on the original topic....
New - Four Positions from a Domain in Google Results Nov 19, 2010 https://www.webmasterworld.com/google/4232376.htm [webmasterworld.com]
IMO, it was one of the most contentious "test" features Google ever introduced, and I remember several Googlers almost apologizing for the "test', but saying that they couldn't ignore the mathematical realities and needed to try it.
I wonder how it will play out this time....
