Crossword clues for Groups of four:QUARTILEStatistical dividing point in a four-group data setMINCEWith 45-Across, not be direct ... or what four groups of black squares in this puzzle do?FORMLETTERSImpersonal notes ... or what four groups of this puzzle's answers do (totaling 11 words)FRATERNITIESFour groups found in this puzzleBELTBUCKLEClothing accessory, perhaps ... or what you can see in each of four groups of circles?OCTETGroup four times the size of a duoTETRAFish that sounds like it should be in a group of fourTETRADSGroups of fourACESSinging group "The Four ___"TOPSHall of Fame pop group The Four __, and last of this puzzle theme's five anagramsTETRADGroup of fourACES'50s group The Four ___LADSThe Four ___, singing groupEMI___ Group ("big four" record co.)COMETS1950s backup group with four top 10 hitsTLCGirl group with four #1 hits in the 1990sTETRADSFours, as groupsLADSSinging group The Four ____BEATLESGroup with the four circled membersCATHYComic strip with "four basic guilt groups"STRINGORCHESTRALarge four-instrument musical groupSWINGSHIFTFour-to-midnight groupLADSThe Four ___ ('50s singing group)THESHUNSIGNBOYSGroup that ignores four-way stops, e.g.?MILLSBROTHERSClassic jazz vocal group originally composed of four siblings, with "The"COVERBANDSTribute groups, or a four-part hint to the starred clues' answersSTRINGQUARTETClassical music group ... or what the four sets of circled letters make up?GAMMAThird in a group of twenty-fourBIGTENNCAA group that will add four new members in 2024TOPSFour in a music groupTOPSFour in a Motown groupTHEROOTSFour-time Grammy-winning rap groupBOYZIIMENFour-time Grammy-winning R&B groupSEALSElite Navy group that's fittingly camouflaged in the four longest answers in this puzzleBREAKINGRANKSSplitting with one's group ... or a hint to the theme found in four puzzle rowsBARBERSHOPWith 63-Across, singing group ... or a hint to the ends of the answers to the four starred clues