Or search: vie, gibe, jibe, peer, quits, rival, tally, tight, backup, equate, modify, mortal, coeval, coequal, compete
2 Syllables: SU
beetle, Cecil, Cyril, diesel, eagle, easel, equal, evil, febrile, feeble, fetal, genial, legal, lethal, measles, medial, menial, needful, needle, peaceful, penal, people, regal, renal, sequel, siecle, steeple, venal, venial, virile, weasel
3 Syllables: SUU
cerebral
3 Syllables: USU
adrenal, cathedral, coeval, congenial, deceitful, enfeebled, illegal, medieval, primeval, remedial, retrieval, unequal, unequalled, upheaval
4 Syllables: UUSU
mediaeval, uncongenial

Found 48 words across 4 groupings. Skipped 13 excess words of a similar stem.