Or search: charon, boater, boatman, waterman
2 Syllables: SU
barium, carrion, clarion, Marion, requiem, variance, variant
3 Syllables: SUU
anyone, anyone's, everyone, everyone's, twentyone
3 Syllables: USU
agrarian, aquarium, barbarian, Bavarian, Bulgarian, equestrian, grammarian, Hungarian, librarian, millennium, ovarian, pedestrian, sectarian
4 Syllables: UUSU
antiquarian, proletarian, Unitarian, vegetarian
5 Syllables: UUUSU
authoritarian, disciplinarian, egalitarian, humanitarian, totalitarian, utilitarian

Found 35 words across 5 groupings. Skipped 6 excess words of a similar stem.