H2O has the ability to display content based on the current user and/or portal. To get what you are looking for, simply create an H2O form and add a Java Script control to the form. In your java script, genereate a hyperlink based on the current users region. To get the users region, simply use the H2O Script Tag for what you are looking for. When the form is loaded, H2O parses your script and replaces the tags with current values.
This is actually a new feature but it's beta and it's final release date is expected to be July 23, 2006