Or search: apostle, socialist, clocksmith
2 Syllables: SU
offerings
3 Syllables: SUU
causative, congresses, goddesses, novices, offices, positive, talkative
4 Syllables: USUU
cooperatives, corroborative, prerogative, provocative, unconsciousness

Found 13 words across 3 groupings. Skipped 1 excess word of a similar stem.