Here are the rules on falling:
At the end of a fall, a creature takes 1d6 bludgeoning damage for every 10 feet it fell, to a maximum of 20d6. The creature lands prone, unless it avoids taking damage from the fall.
One of the effects of the Enhance Ability spell is called Cat's Grace:
The target has advantage on Dexterity checks. It also doesn't take damage from falling 20 feet or less if it isn't incapacitated.
Let's say Bob is affected by Cat's Grace. Bob grapples Rick and starts dragging him forward, but then a trap opens below both Bob and Rick into a 20ft deep pit, making both of them fall down. We know Bob does not take falling damage, but what about Rick? Does Rick take the 2d6, or does he also take nothing, thanks to Bob acting as some sort of cushion?