Gee, that’s intriguing. Got any links or anything? :)
The first was William Irvine who founded the “Two by Two” groups. He went to Jerusalem in hopes of being one of the two Witnesses.
I was raised in this group. Thankfully a GRACE believer, in 1973, shattered the chains of legalism from me and I have been free ever since.
I now go to a Baptist church (but am not a baptist) Google “Cooneyites”. Same group but took after a different preacher William Cooney.
https://www.meta-religion.com/New_religious_groups/Groups/Christian/cooneyites.htm
http://www.killicomaine.org/pdf/other_religions/15%20The%20Cooneyites.pdf
The second were a group of the Foundation of Ubiquity (FOU)I remember reading and hearing of them on the news back at that time.
https://www.nytimes.com/1982/07/04/us/2-cultists-hijack-a-bus-then-kill-themselves.html