1 Syllable: S
Charles
2 Syllables: SU
awful, Basel, bottle, bronchial, brothel, causal, Connell, consul, Cromwell, docile, fossil, gospel, hobbled, hostile, jostled, lawful, model, modelled, models, Mongol, mottled, nostrils, novel, nozzle, offal, Ronald, snarled, squabble, throttle, tonsils, topple, wrongful
2 Syllables: US
withdrawal
3 Syllables: USU
apostle, colossal, debacle, ensemble, Macdonald, McDonald, remodel, remodelled, unlawful
4 Syllables: UUSU
horizontal, unexampled

Found 45 words across 5 groupings. Skipped 11 excess words of a similar stem.