No, I don't think it is possible in the way you describe. Whether splines have their own IDs or not, that wouldn't make a difference to a sweep made out of them, which is just a generated new polygon object with its own texturing and UV coordinates. However, you can use a Correction Deformer and Transferred Polygon Selection tags to apply multiple materials to one sweep, so for practical purposes, the answer to your question is actually yes.
To do this make the Correction Deformer a sibling of the sweep within a group null, and use it to access the Poly mode, and double click each cable (or select one poly and do U,V), which should select all connected polys - ie all the polys of one part. Make a selection tag of that on the DEFORMER, then move that tag to the live sweep where you can use it to limit materials to that section.
But I'd venture that a slightly quicker / simpler way to go here is to make cylinders / sweeps per 'cable', texture them independently, then arrange and group them as you need (I used a radial cloner for this) and spline wrap the whole lot into your final cable shape along the path spline you were originally using for your sweep. This sort of thing...
CBR