NATS 3 Question about custom join pages

[Simon]

There's a sponsor we want to promote via a special mailing to our newsletter subscribers. They've agreed to let us offer special lower prices that are not part of their usual pricing to the general public, so we'd like to be able to point the newsletter readers to a custom join page which would only be seen by surfers following a special link we give them in the mailing. But the sponsor is having trouble with NATS 3 as far as being able to set up a join form that works that way.

The code we're testing does change the prices in the little drop down menu on the join page, but aside from that, the page is exactly the same as seen by all surfers to the site, including wording at the top which refers to the usual higher prices instead of our special prices. So unless our subscribers scroll down they won't see the special prices, and even if they do see them, they may be confused seeing one price at the top of the page and a different one in the drop down selection menu.

The last thing I want to do is create uncertainty at the moment of decision, so I'm hoping we can have the sponsor make a join page that only contains the special prices, but keep that join page from being seen by the rest of their traffic who'll be paying a higher price as usual.

Anyone here have enough experience with NATS 3 to know if this is even possible? The sponsor said they asked someone from TooMuchMedia and were told it couldn't be done for some reason. But it sounds like such an easy thing to do (if you're NOT using NATS anyway), so I'm hoping the person at TMM didn't exactly understand what they were being asked.

So... does anyone know if this can be done with NATS 3? And maybe how to implement it? Or even know how to achieve the same result another way if the sponsor is using NATS 3?

Any help appreciated.