Or search: file, mail, slate, enrol, enroll, patent, timber, timbre, furnace, recruit, storage, campaign, inscribe, perceive, register
2 Syllables: SU
settler
3 Syllables: SUU
barrister, creditor, editor, Eleanor, Hereford, mariner, register, Senator, severer, treasurer
4 Syllables: USUU
competitor, developer, inheritor, investiture, progenitor
5 Syllables: UUSUU
primogeniture

Found 17 words across 4 groupings. Skipped 13 excess words of a similar stem.