2 Syllables: SU
foreigner
3 Syllables: SUU
auditor, chronicler, commoner, gossamer, lawgiver, monitor, officer, oftener
4 Syllables: SUUU
kilometers
4 Syllables: USUU
astrologer, astronomer, barometer, biographer, depositors, expositor, geographer, idolaters, philosopher, photographer, thermometer
4 Syllables: UUSU
kilometres

Found 22 words across 5 groupings. Skipped 16 excess words of a similar stem.