Or search: leg, leap, nigh, span, gauge, milage, mileage, spacing, yardage, farness, interval, outstrip, nearness, closeness, elevation
3 Syllables: SUU
differences
4 Syllables: USUU
appearances, existences, indigenous, religionists, remittances, resistances
5 Syllables: UUSUU
abolitionist, interferences, reminiscences

Found 10 words across 3 groupings. Skipped 1 excess word of a similar stem.