Very good point, the comparison isn’t 1:1. As I understand it (not at all a mobster myself just a voracious consumer of mob content), today A would say to B “I’m with Z’s family/crew” if they were from the same area, and might specify the location if they weren’t from the same area. But generally they wouldn’t talk Cosa Nostra stuff if they were strangers, even if they were both in the mob. There would need to be an intro made between them.

In 1875, B would likely have introduced themselves to C using the same ritual above, but perhaps with A hinting to C to kick it off by… complaining about a toothache to B lmao.