I'd like to do the same for my tail/marker lights. I could turn them off when chased and disappear into the night a little easier. More of a novelty for my fantasy but.... makes me happy thinking about it.
since they're all on one fuse, its easy.
make a wire that goes like this:
Spade terminal --> fuse holder --->long wire-->switch--> long wire back-->spade terminal.
pull the fuse for the lights.
use a meter to find the power side of the fuse holder for the lights.
put the spade terminal with the fuse holder next to it, in the power socket (this is important)
put the other one in the other fuse socket.
now when the switch is on, the lights all work normally.
when you flip the switch, its the same as the fuse blowing... none of the lights have power. (except the headlight, its separate)
if you use a double switch, you can include the headlight while keeping the circuits separate.