Or search: upset, disorder, adenopathy, aldosteronism, thyrotoxicosis, hypoadrenalism, hyperadrenalism, hyperpituitarism
3 Syllables: SUU
credulous, decorous, delegates, edifice, estimates, Federalist, garrulous, generous, Genesis, Methodist, Pegasus, perilous, prejudiced, premises, querulous, recklessness, requisites, resinous, restlessness, tetanus, treacherous, venomous
4 Syllables: USUU
asparagus, assemblages, confederates, degenerates, Emeritus, incredulous, prerequisites, ungenerous
5 Syllables: UUSUU
conscientiousness

Found 31 words across 3 groupings. Skipped 1 excess word of a similar stem.