Or search: physics, isotropic, isotropous, superposable, indistinguishable
3 Syllables: SUU
chemical, plentiful
4 Syllables: USUU
nonsensical
5 Syllables: UUSUU
academical, biochemical, ecumenical
6 Syllables: UUUSUU
incomprehensible

Found 7 words across 4 groupings. Skipped 1 excess word of a similar stem.