3 Syllables: SUU
dualism, nihilism
4 Syllables: SUUU
despotism, fatalism, federalism, feudalism, formalism, journalism, mechanism, Methodism, naturalism, pessimism, pluralism, socialism, symbolism, television, terrorism, vandalism
5 Syllables: USUUU
colonialism, imperialism, industrialism, materialism, metabolism, paternalism, provincialism
6 Syllables: UUSUUU
sentimentalism
6 Syllables: UUUSUU
individualism

Found 27 words across 5 groupings. Skipped 1 excess word of a similar stem.