put a whole domain 'on hold'

[Mike K]

Hi all,   I did a search from the archive to find no info on this...   I run a webhosting company.  When a client doesn't pay, we simply move their public_html directory and put an ad for our services in its place.  However, many times, I have noticed that for the month of 'on hold' status, these people continue to utilize their e-mail.   We've got vpopmail running right now.   My initial thoughts were to simply change the pop3 account passwords, but I honestly can't sit here changing 200 passwords.  Plus, changing them back would be a b..... would be not fun.   Is there a way that I could set a whole domain to a 'hold' status, so all of the mail waits for them, until the hold is removed?   If so, will this method also prevent people who have their mail simply forwarded to another address from getting their mail (it should)?   Thanks for your time.   -Mike