Proxy of some sorts

[Steven Schermerhorn]

I am wondering if someone knows of software out there that will help me
accomplish something.

We are a subscriber to a website that grants us access to it based on the
requesting IP address. I would like to allow staff to logon to the intranet
and then 'trick' this website into thinking it is serving one of our IPs
when in fact it is a user off-site.

I realize this can be done by setting up a proxy, however setting people's
computers up to go through a proxy isn't an option. Is there software out
there that can redirect/proxy websites.

-Steven Schermerhorn