Using /etc/aliases with groups

[Eucke Warren]

I have been googling and I have not hit upon a keyword combination that will shed light on this.  I would like to create a Group for mass emailing users on a server.  I have tried  adding a line like

everyone:        users

but the email ends up being rejected.  This is a sendmail setup and, yes, I did run newaliases after altering the /etc/aliases file.  Anyone doing this?  Suggestions on how to implement?  I intend to only make the group alias live when we want to do the mass Email and will disable it once it is sent to prevent unauthorized use.

Thanks guys!

-Eucke