Or search: emphatic, stressed, emphasised
3 Syllables: SUU
centralized, emphasise, emphasize, enterprise, enterprize, generalized
4 Syllables: USUU
decentralized, exemplified, exemplifies, exemplify, identified, identifies, identify, indemnify
5 Syllables: UUSUU
unidentified

Found 15 words across 3 groupings. Skipped 1 excess word of a similar stem.