This connector is designed to hold your cables in place. It has one hole for a cable with a about 4.7mm diameter and one with 5.5mm. So your brake cable and shifter or dropper post cable should fit. It is made that way so it can fit slightly bigger or smaller cables. 

I also uploaded a design that is not that long (only 6mm) if you think that is looking better.

Update: added a step file