Is there anything that supports the gang spacing of locking devices. For example if you want to install (2) L5-20 receptacles you'd typically use 3 device boxes and the center to center between the two would be 3-5/8". They make that matching plate and everything. Are you permitted to mount them side by side @ 1-13/16" center to center between? I can't find matching cover plates. I have an application that wants 4 ganged together using only 4 device boxes.