A museum-l newsgroup would be super.  Newsreading programs generally
differentiate between to-the-list and private replies, with different
commands, so the reader in no case needs to manually input the desired
address.
 
The additional advantage to having the messages on usenet is that one
needn't unsub or go nomail when you're away for a few days -- since the
messages aren't in your mailbox, but in a spool somewhere, you can simply
catch up when you return without fearing for your quotas.
 
[Usenet = "Netnews", as far as I know].
 
--bayla