Preventing on-hit/spell effects triggering

[Razakai]

One of my addon trees has a sustain that causes Necrotic Aura to deal minor cold/darkness damage to those inside it. On it's own it's a decent source of damage, but one problem is that the class also has some sustains that proc from cold/darkness damage, and of course there's various items that trigger on spell hit. This makes it absurdly strong.
So is there a way to flag a particular source of damage, damage type or spell to ignore all effects and do nothing but deal damage? So no interaction with anything else.

[HousePet]

Nope

[Razakai]

Blah, I'll have to nerf the damage further and make my sustain only apply to select talents rather than damage types. Thanks.