I know from your previous posts that the survey process is a key interest for you. Your Customer Engagement Executive (CEx) will help you get these questions addressed with an Ariba expert. Thanks again for sharing your experiences at Ariba Exchange.
Ariba Exchange Community Manager
I know at the last company where I worked, the link opened directly into the survey. You may want to check your email template and determine what token is being used for the survey link.
Additionally, if you want to hide specific items from users, then the best way to handle this is through group assignment. Filters can be setup based on classifications found on the workspaces themselves.