How can I mimic a newsgroup in WP?

After a flurry of emails from extended family members talking about our genealogy and family history, I created a mail list through my web host, and then set up a family WP site with Atahualpa.

I'd like to find a way to collect and post all the emails on the WP site, without having each one show up on the blog as a separate post. Is there a way to do that? I've experimented with using www.posterous.com to create a post from an email (it takes the email and makes a post on a site Posterous maintains, and then publishes that to other sites such as a WP blog), but would prefer something more like Google Groups or the old style newsgroups. Ideally, people could choose to get notified each time an email came in, or only once a day, or could go visit the site when they wanted to see the activity.

By the way, Posterous is pretty cool - it allows you to email almost anything to post to the site, including photos and I think video too.

I know this question does not have to do with Atahualpa per se (although I use Atahualpa on several sites including this one) but would appreciate any ideas or suggestions!