Here's my schematic solving your wiring need:

A description of how I used it is at
http://www.horseapple.com/Valkyrie/Tech_Tips/VTX_signals/vtx_signals.htmlThis tech tips page explains the logic of how the relays are used.
If your wires already provide the signal separated from the brake and turn lines, (you don't need to parse them) on the single wire from each side, and has another wire for the running lights, then you can simply eliminate the relays from this circuit - just bring in the brake/turn line for each side instead, in it's place. Easy-peasy.
I will be wiring my 97 Tourer's rear marker lights with this circuit, as well as the Super-Highlighter, both of which I already wired the same on Deerslayer. Here's the Super-Highlighter on Deerslayer:
https://www.youtube.com/watch?v=0TkRl9i8Ad8