If this feature is mainly intended for the following feed, then we should consider hiding the option in other feeds. I’m not sure if it’s just me, but when I enable grouping, I often can’t scroll through the list, and the mouse cursor turns into a loading icon. I agree that the only real solution is to use a caching database. However, I’m not sure if we should add one to Jumble, since many clients have run into various issues caused by improper cache handling.