Or search: mole, groin, jetty, barrier, seawall
1 Syllable: S
boil, boy, Boyle, boys, broiled, choice, coil, coin, coy, Croix, Deutsch, Deutsche, doit, Doyle, droit, Floyd, foil, Freud, goin, groin, hoi, hoist, hoy, jeune, join, joint, joy, Joyce, joys, Lloyd, Lloyd's, loin, loyal, Moines, moist, Neu, noise, Noyes, oil, oy, poi, point, poise, Roi, Roy, Royal, Royce, soil, soy, spoil, spoilt, toil, toy, Troy, voice, void
2 Syllables: SU
Detroit, exploit
2 Syllables: US
adjoined, adjoins, adroit, annoy, anoint, appoint, avoid, conjoined, decoy, deploy, despoiled, destroy, devoid, disloyal, Dubois, embroiled, employ, employes, employs, enjoin, enjoy, recoil, rejoice, rejoin, Savoy, subjoin, unspoiled
3 Syllables: UUS
disappoint, Illinois, overjoyed, unemployed

Found 89 words across 4 groupings. Skipped 41 excess words of a similar stem.