In physics, if A is part of B, it means it's a spatial part. I think the "parts" of a conscious experience are part of it in some other way. I say this very metaphorically, and only metaphorically, but it's more like the way that polyhedra have faces. The components of a conscious experience, I would think, don't even occur independently of conscious experiences.

There's a whole sub-branch of ontology concerning part-whole relations, called mereology. It potentially encompasses not only spatial parts, but also subsets, "logical parts", "metaphysical parts" (e.g. the property is part of the thing with the property), the "organic wholes" of various holisms, and so on. Of course, this is philosophy, so you have people with sparse ontologies, who think most of this is not really real, and then you have the people who are realists about various abstract or exotic relations.

I think I've invented a name for my own ontological position, by the way - reverse monism. I'll have to explain what that means somewhere...