Is a composite item an Individual, or a Group of things?
A composite item is made of several different substances, so it could easily be classed as a group.
However, the magic is in all of the parts, binding them together etc. If any of them are removed it "breaks" the device. So there is an argument that says they are Individuals. A man is an individual, even though he is composed of a body, arms and legs.
The thing that separates a man from a collection of parts is that a man is a distinct thing - there is something that ties them all together, they belong together. I think that the same would hold for a composite item.