This video demonstrates the relative ease of pulling together a custom cable in the Zuken E3 tool. This video draws an Ethernet cable consisting of two RJ-45 connectors and a CAT-6 cable.
Though Zuken E3 has much of the look and feel of a schematic tool that one would use for PCB schematic design, this tool was constructed to handle both the mechanical and electrical aspects of system-level design. One must remember that EDA tools are designed for electrical schematic designs, dimensionless by their nature. This is why making a cable design with any intelligence (i.e., properties, parameters, attributes, etc.) in an EDA tool is complex.
The E3 tool is truly a system engineering tool; cabling is one of several core capabilities.