ToME: the Tales of Maj'Eyal

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.

Nope

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