Auto Detect Texture Suffix

I have naming convention like
_N for normal, _R for rough,
the problem is that i cant find where i set the engine to automatically
treat these differently. Roughness will always end up in sRGB so i have
to manually turn that… stuff off. All the time.
I want Unreal to do that for me, in Unity i do that by writing
simple c# override, but here its all obfuscated i have no idea how can i
achieve this.