mail aliases, mailing lists and netscape mail client

[Sundar]

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