mob trigger with specefic item?

Hi there!

i am seeking a way, to make a custom mob that triggers a skill when you click it with a diamond or something,
or drop it near the mob,
is this possible?

Example: (does not work, ikr)

DiamondEatingPig:
Type: PIG
Display: '&bDiamond eating pig
Health: 50
Damage: 0.5
Skills:
- skill{s=ShootFireWorks} @target ~onInteract:diamond

Thanks
AnimalMace