Or search: rep, legislator
2 Syllables: SU
conference
3 Syllables: SUU
complement, confident, consequence, consequent, consonance, consonant, continence, continent, Donovan, Jonathan, monument
4 Syllables: USUU
incompetence, incompetent, incontinence, preponderant, reconnaissance

Found 17 words across 3 groupings. Skipped 4 excess words of a similar stem.