How can I set different homepage for when I am logged to different networks?

Hi
Our company computers are set to open our intranet page for default
homepage on Internet Explorer. This page can only be opened within the
company network.

When we log on computer outside this network the page cannot be opened
and we only get an error message.

Is it possible to set IE to open another webpage as homepage when
network is not company? And how can this perhaps be done?

Hoping somebody knows this type of challenge.

Thanks,
Karin