Excellent question, but unfortunately no.

I just logged into the GMail account we're sharing for this purpose and looked at the email. It looks like the user actually did the proper thing. He BCC'd all the addresses and put the sender's address in the To: field. Both are what Google suggests. I then looked at the bouncebacks, and from what I could tell, they are all actually from Google, not the recipients' mail servers. The link the bounceback sends you to then suggests using various sites like Google Calendar and Youtube to send out massive alerts to users.

The problem with this is these sites are for very specific purposes. The email we're currently trying to send out is to inform people of two things: the existence of a website (and a Facebook page), and to request that they take a survey on the website. One of the things the survey will decide is which of five dates the reunion will actually take place on. So that eliminates a Google Calendar event email. Argh.

For now, I think I might try just sending out small batches of emails, sadly. Hopefully there won't be many bouncebacks...