Signal placement in flat ribbon cable, FPC or FFC with digital and power signals
If your 7 wires of VDD are well-bypassed at the load end (using L+C low pass filters), then the AC behavior will be as quiet (or as trashy) as the Ground wires.

Fundamentally, use the bypass capacitors to form the fabled AC_short to between two wires: in this case, AC_short the VDD wires to the Ground wires.