You won't be able to do anything special in the settings bundle. It's static, whatever you compile is what all users will see. If you want special behavior, there are two ways to do it:
Put it in the app itself and only allow the user access if they have the right credentials. A secret gesture could work too, but is a little dangerous because users may accidentally find out about it.
Use a different target/scheme or compile-time conditionals (using
#if
) to build two different versions of the app, one that does include the special configuration and one that doesn't. Personally, I would go for this option, but it may be a little harder initially.