Why do imposible to make sectional copy like with a floppy?
CD hasn't rounded tracks. There are tracks along spiral and many session consist of many tracks, which consist of many sectors. A sector's data are alternate and distribute to large area.
The sector's format is standard, but there are many sectors.
Ability to read some parts of CD depends on firmware /firmware download / flashing/ CD. Some CD record players cannot to understand multysessional disks or read audio tracks like a digital data.