"This preference affects only HTTP redirects, not redirects with HTML meta tags or JavaScript." So if the shorteners use (or can be configured to use) different

"This preference affects only HTTP redirects, not redirects with HTML meta tags or JavaScript." So if the shorteners use (or can be configured to use) different redirect methods, it might be possible to get around this limit. However, you'd have to create a chain composed of shorteners each of which either doesn't recognize the next one on the list, or doesn't do any "security" checking at all.