Unique hit sounds system

My combat collision system is involved of two parties, attack and entity(being hit).

I want to add specific effects on collision, depending on the properties of parties involved in the collision. is it a slice through flesh? a bullet hitting metal? I might want different SFX/VFX for each of those.
Attacks carry attack_properties which aren't a class so every time I want to redesign it it takes going through everything I've made so far to edit it.

as such I'll go for a bandaid solution instead.
groups called "material_metal" "material_flesh" "type_slash" "type_bullet" etc
I'll be able to check whether both parties have groups that I set up in advance to have unique SFX/VFX, overwriting the generic one. if they do, I play the new ones instead.
A metallic thud if hitting metal, softer if hitting flesh, metal and metal producing sparks possibly.

I think it's a good solution given my constraints, this being a band-aid solution due to not knowing any better. First game, less than ideal solutions.