exactly. Murder is most likely a solitary "sport" but was it always? Did occasionally some of them work together? Do you wonder how many of the non-killers thought of certain people in the group when body parts were discovered? Did certain snipets of conversation come to mind?
In the book "Bloodstains" published by H.H. Holmes' great-great-grandson, I seem to recall Holmes writing in his diary something to the effect: "There is another one of us here" supposedly in London during the time of Jack the Ripper, even though the g-g-grandson tried to paint Holmes as the Ripper.
So, since multiple SKs were working at the same time, do you think they recognized there were others like them? Did they know who was doing what?
We have speculated about Bittrolff and RH knowing each other, perhaps working together, perhaps RH following and copying JB . . . . wonder if we'll ever know?
Because of my own recollections when something jogs my memory, I feel certain members of that group do recall conversations, incidents that made them wonder at the time. People who moved in that group surely have very unsettling memories, wouldn't you think? Wonder if any will ever be willing to talk "on the record"?