Changing textures upon impact of missile

[Collegia Titanica]

I'd like to know how to make the following scenario:

Ice Nuke:
Ice warhead explodes -----> In a certain radius of the explosion the textures change to ice versions of themselves (From a normal custom texture to their frosty version) (METAL05->FMETAL05)

This large radius not only freezes all enemies inside it (I know how to do this), but also changes textures.

ProtoScRiPt:
IF texture included in this radius, then change texture to F(whatever-texture-affected)
Perhaps separate definitions for all available freezable textures would be needed {metal xx, grass xx, wood xx}


Just a curiosity thing, nothing major is planned.