Or search: modify, democratise
3 Syllables: SUU
authorise, authorize, colonize, crocodile, dramatize, modifies, occupied, occupies, occupy, oxidized, qualifies
4 Syllables: USUU
apologise, apologize, economize, hypothesized, monopolize, preoccupied, unauthorized, unoccupied

Found 19 words across 2 groupings. Skipped 6 excess words of a similar stem.