Or search: blimp, bourbon, reactionary, conservative
3 Syllables: SUU
burgesses, furnaces, purchases, purposes, surfaces, surpluses
4 Syllables: USUU
affirmative, alternative, conservative, disturbances, divergences, interpretive, observances, preservative, superlative

Found 15 words across 2 groupings. Skipped 2 excess words of a similar stem.