The way that I play, I group dwarves so that they always specialize in just one profession that can give rise to a strange mood, and the rest of the professions they have won't be moodable. This way, I kind of get some control over what artifact gets produced.
So, stuff like weaponsmithing, armorsmithing, blacksmithing and metalcrafting usually gets grouped with furnace operators, farmers, brewers and cooks. That way I can let them hit a level in their moodable skill, disable that labor, then have them be full time farmers or whatever until they get a strange mood. This is only if I already have obtained or trained a dedicated legendary for that profession and there are excess smiths to go around. Likewise, stone crafters go with engravers and miners go with masons because same grouping of moodable skills.
Otherwise, the professions are grouped so that they can perform other related jobs in the same family of professions. So if a soaper dwarf is free, they will be able to just focus on lye making and then soap making, instead of having to wait for another dwarf to come around and make soap from the lye. So stuff like soapers go with potash makers and lye makers, tanners go with leatherworkering and butchery, and mechanics go with building designers.
As for other kinds of groupings, I usually disable stone hauling on my miners so they can mine continuously instead of mining a vein, grabbing a rock to haul, then coming back to mine again.