mail aliases, mailing lists and netscape mail client

Hello,

I have couple of mail aliases for my base e-mail address(
linux@esaravana.com ). Eg, adrenaline@esaravana.com for my rock climbing
group. I use appropriate alias to subscribe to different groups and
receive mails. The problem comes when I post messages to the group. The
mail goes back as my base e-mail address( linux@esaravna.com ), rather
than as my aliased e-mail address( adrenaline@esaravana.com ) and gets
rejected.

Is there anyway I can add mail aliases to Netscape mail client and
choose appropriately as I send mails. Or should I do anything on my mail
server.

I am running RedHat 7.1 with Sendmail as my smtp server.

Sundar