Does Eeschema support this yet? - Assemble hierarchical schematics into multiple root schematics.
from http://www.mikrocontroller.net/wikifiles/a/ab/HierarchicalSchematicsAsBuildingblocksAtKiCad_RevC-EN_06May2015.pdf > p4, written in 2013:
Hierarchical schematics can be used as building blocks to create new schematics.
KiCad does not support this with functions, you have to use workarounds.
There are two types of hierarchy…
The second consists in creating components in the library that appear like traditional components in the schematic, but which actually correspond to a schematic which describes their internal structure.
This second type is used to develop integrated circuits, because in this case you have to use function libraries in the schematic you are drawing.
Eeschema currently doesn’t treat this second case.