2 Syllables: SU
copious, glorious, Grotius, laureate, odious, opiate, Proteus, Soviet
3 Syllables: SUU
holiness
3 Syllables: USU
appropriate, associate, censorious, commodious, erroneous, harmonious, inglorious, laborious, melodious, notorious, opprobrious, Theodosius, victorious
4 Syllables: UUSU
acrimonious, ceremonious, meritorious, parsimonious

Found 26 words across 4 groupings. Skipped 1 excess word of a similar stem.