2 Syllables: SU
abo, anno, ano, aro, arrow, Austro, auto, backbone, Barrow, Blackstone, borrow, Bravo, Caro, Castro, facto, fallow, follow, Gladstone, Glasgow, grotto, hallow, Harrow, hollow, lago, macro, Malo, morrow, Moscow, motto, mottoes, narrow, Otto, Palo, Paso, Paulo, Roscoe, sallow, shadow, shallow, sorrow, Stockholm, Strabo, swallow, tallow, Tasso, topmost, wallow
3 Syllables: USU
4 Syllables: UUSU

Found 66 words across 3 groupings. Skipped 3 excess words of a similar stem.