The VThe V-Ray Multi-Sub Tex texture distributes multiple textures to many objects via one single material based on specified IDs or random distribution.
In the image shown here, Multi-Sub Tex's Get ID from parameter has its type set to Object ID. Each part of the ball is assigned a texture. The Multi-Sub Tex is then assigned to the diffuse channel of a single V-Ray Material.
Any texture can be replaced via the Replace With New Texture () button, which activates when you select the texture to be replaced. If the texture is an instance, all copies are changed as well.