Lively, I do not think that such rings predate the internet.
I believe that in all the cases involving grooming by rings, the grooming was done on line.
There may be a few exceptions, but I have not heard of them.
Have you?

Lox says there is no "new" crime of street grooming.
I have never before heard of men combining in teams to procure children in their hundreds from public places to rape them.

Having said that we now know it has been going on for years hidden from public knowledge, and the perpetrators mostly bps.