Digging this up...
Did you get anywhere with this? I'm in the same position. I'm trying to push Yahoo for access since the moderator seems long gone from other posts I've seen (since about 2008).
I've emailed the group owner email address HackTheIBusfirstname.lastname@example.org but that probably goes into the same blackhole as the join requests.
Anyone else here reading a member of the group? I was a long time back but seem to have lost that access (or the account it went to).