The wire blocks are easy to alter, this image shows how the ends of the wire are pushed into the plastic holding block. If you look closely a tag secures the wire into the block so to pull the wire free you just have to push the tag down with a small screwdriver and the wire will slide free. This is worth doing wherever you will be drilling holes, afterall it is a far smaller hole for three wires to pass through than it is for three wires with this plastic block. Once the wires are through where they need to go you can reinstall them into the block.