Hi Arnel,

I figured this out. It was actually quite simple. It's the way that Yahoo groups are supposed to function.

Yahoo groups do not see the address from which the message was forwarded. They look for the From address field to see if it matches an address in the member list for the group. If there is no match, then Yahoo groups simply discards the message. This way the group admins don't have to deal with deleting tons of spam the way the admins for some Mailman lists have to. A sender who is not a Yahoo group member will get a bounce message, but they aren't very descriptive messages. And, this is the kicker, if you happen to be using GMail, the bounces are likely to go into your spam folder if you get a lot of them in rapid succession, so you might never see them.

So, there wasn't anything actually broken. It just looked broken.

Cheers,
Randy