Sounds like you are looking to do a hybrid system. That is what we use.
There is no block diagram, just a wiring diagram that looks like a schematic.
All the symbols (that have data attached) are placed on the wiring diagram to indicate the connection information and their schematic symbol. We lay out the wiring diagram traditional schematic but the lines between items are actually the wiring diagram rather than unspecified connections. Unlike a true schematic where connections to multiple points are nebulous, this shows if a wire goes to daisy chained terminals or actual splices.
Setting up the data is too complicated to do in a quick reply. You really need to get a consultant to explain how this works and how to set up all the data files.
The splices are end specific. The wires on each end stay on those ends when the harness is routed in Creo Parametric.