Wireless question concerning email

How can I specify a different outgoing email server at home than I use at work that works automatically?

I use my MacBook Pro in both places. When I am at work my email uses the same Incoming and Outgoing servers. My wireless ISP, in order to control spam, requires that all email go through their servers. That means I cannot get an email to go through unless I use their server for Outgoing.

Can I force my Mac to use different email configurations based on whether I am connected to an Ethernet network at work or a wireless network at home?

Thanks for any help,
Kboard6

Sounds like when your plugged in at the office your behind their firewall, which allows SMTP connection to their server. However when you get home your unable to establish this connection because of the security policy in place by your company. I would setup multiple mailboxes in Mac Mail. One for work and one for home. Work ISP and Home ISP, when you get home you'll just get an error that says it can't use your work mailserver settings and thus ask if you want to default to your home mail settings.