Modifying GSA Public Proxy List Testing Source

I'm testing a few new methods with GSA and needed help figuring out GSA's public proxy testing feature. I'm looking to compile a large list of anonymous proxies that can be used for posting on websites rather than scraping search engines.

How do I setup the proxy tester to check for ONLY anonymous proxies and NOT for their ability to scrape the default search engines (like bing.com)?

Never have figured out a solution, figured I'd try here again before asking elsewhere.