I made a small triple cable holder for Multiboard.
 

The part has a directional snap (with screw hole if you want to use the backside too)

It fits within one unit, so you can place things right next to it. 

top of the holes are a bid wider so the cables will stay in. I think it works with al my cables, but no promises haha
 

I'm busy uploading all my Multiboard designs, so feel free to check my profile!