Proper group grinding is for full parties, and while dungeons will be auto-configured with the dungeon finder and designed so basically any group of people thrown together can complete it for the exp bonus, a dedicate good support is something that a well designed pre-made group would benefit most from, thats the kind of thing open world grinding is really meant for, and one of the reasons people like me really wish it was more viable.
If people dont recall, you get a massive exp bonus if you use the dungeon finder instead of actually forming your own party to run the dungeon with. While some people might argue things would go smoother with a pre-made group, the fact is the limited runs per day you get mean even if it takes twice as long to run the dungeon, you are still getting way more exp:day by just letting the game automatically shove you into a group.