Or search: mt, tap, humor, strip, humour, exploit, montana, potable, protein, aliment, drinkable, nutrition, colostrum, nutriment, sustenance
2 Syllables: SU
billing, building, chilling, drilling, filling, gilding, killing, milling, pilgrim, shilling, spilling, thrilling, tilings, tilling, tilting, Wilkins, willing
3 Syllables: USU
distilling, fulfilling, instilling, rebuilding, unwilling

Found 22 words across 2 groupings. Skipped 3 excess words of a similar stem.