2 Syllables: SU
Biscay, blissful, bristle, Bristol, cereal, cheerful, chisel, civil, crystal, dismal, distal, fearful, fiscal, grizzled, Israel, Michel, missile, Mitchell, pistol, rivalled, serial, shrivelled, swivel, tearful, thistle, trivial, vigil, vitriol, whistle, wishful, wistful
3 Syllables: USU
arterial, bacterial, baptismal, convivial, dismissal, epistle, ethereal, imperial, initial, judicial, material, official, peripheral, venereal
4 Syllables: UUSU
artificial, beneficial, immaterial, interstitial, managerial, prejudicial, sacrificial, superficial, unofficial
Found 54 words across 3 groupings. Skipped 14 excess words of a similar stem.