We're working on a Google Form where people can suggest Groups to be archived (and mark them as 'locked' or 'private' to show that someone needs to become a member). It will feed into a spreadsheet like this one https://docs.google.com/spreadsheets/d/1TDxsfAl1lf20habGWyF_Sp-vIpNWnMyLhbXKcQYTQPo/edit#gid=0

It will be up to fans to find people who are members of the Group. You can also try sending a message to the list owner by NAMEOFGROUP-owner@yahoogroups.com - it is the same email that is used when you subscribe but maybe a different subject line?