Or search: pad, tick, futon, pallet, paillasse, palliasse
2 Syllables: SU
average, cameras, fastenings, happenings
3 Syllables: SUU
actresses, damages, garrisons, gatherings, labyrinth, narrative, Nazareth, packages, palaces, passages, pasturage, patronage, sacrilege, savages, stratagems, vassalage
4 Syllables: USUU
anathemas, collaborative, comparative

Found 23 words across 3 groupings. Skipped 2 excess words of a similar stem.