Or search: bonding, fastening, attachment
2 Syllables: SU
broadening, doctrine, jostling, modeling, offering, quarreling, softening
3 Syllables: SUU
auditing, blossoming, bothering, fostering, gossiping, honoring, honouring, modelling, profiting, promising, prospering, slaughtering, tottering, vomiting, watering

Found 22 words across 2 groupings. Skipped 1 excess word of a similar stem.