[Mailman-Users] Maillist spam issue

[liuhao]

Dear Mailman,

I am currently maintain the maillist for *ecfs.com.au*.
we are now facing a issue that, some members want to unsubscribe from the
mail list, and they just reply the mails we sent to them, meanwhile the
email they replied went to every members' mail account on the list.

How could we stop this?

Thank you very much.

Cheers!

-- 
Darren, LIU HAO