Or search: ash, hue, mix, barb, blur, boil, clot, cook, dope, edit, lace, lend, nick, pall, redo
3 Syllables: SUU
authorise, authorize, codified, colonize, dramatize, modified, modify, qualifies
4 Syllables: USUU
apologise, apologize, economize, hypothesized, monopolize, unauthorized

Found 14 words across 2 groupings. Skipped 5 excess words of a similar stem.