Or search: burnup, spending, depletion, expending, disbursal, consumption, disbursement
3 Syllables: SUU
Emperor, engenders, pensioner, temperature
4 Syllables: USUU
adventurer, expenditures
5 Syllables: UUSUU
primogeniture

Found 7 words across 3 groupings. Skipped 5 excess words of a similar stem.