Hook texture loading in Runtime

I read many posted about handling different resolutions. But all they say that I should do it programatically and can't use Property inspector.

In past when I developed without Unity I had 3 folders for textures: t1, t2, t3

 t1 -> tex1.pvr 512x512      // non retina iphone
 t2 -> tex1.pvr 1024x1024  // iPhone Retina or iPad 2
 t3 -> tex1.pvr 2048x2048  // iPad3 + 

LoadTexture('tex1.pvr') was selecting texture based on screen resolution

Is that possible to do something like that in Unity?

e.g. I put texture t3/tex1.pvr in property but some hook replaces first folder in path according to resolution.