Automating Change of Default Account

Does anyone know a way to change the Default E-mail
Account depending on the way you login? Or by Network
Connection?

I have Windows 2000 and login through Novell as Workgroup
when I am home through DSL and through Novell on a network
when I am at work. I have to send my e-mail through two
different accounts, depending on where I am. SO many
times, I've typed an e-mail, hit Send and it goes nowhere
because the default account is set to be the other
account. So I have to change the sending account and hit
Send again, or remember to check/change it for each e-mail.

Is there a simplier way to do this? I don't want to have
to change my default e-mail twice a day.

Sharon