Post Secure Link Options

[TracyL]

I currently have a membership site setup once someone logs in it takes them to a page where they click on a button that is setup as:
<form action="http://www.xxx.com/" method="POST">
<input type="hidden" name="siteid" value="xxxxx">
<input type="hidden" name="theme" value="standard">
<button type="submit" style="border:0px;background-color:#FFF;color:blue;text-decoration:underline;cursor:pointer;">Get Access</button>

The link that they are going to is a part of our website and owned by us but not hosted by us. We use Post so that someone can't just copy the full URL and get access without coming through the membership login. The membership portion of the site is through WordPress.

We have a corporate client that wants to provide a link to all of their employees so that they can bypass having to register to get access. My thought is to provide them with a link so that when employees click on the link it does a redirect and takes them directly to end page. Is there a way to do this? Provide a link and then that page redirects via the same type of Post Secure as above?

Thanks!