Here are lots of ideas for black and white gowns.
In west we have a concept for bridesmaids. That is a good idea. Bride and her friends shop together and know what they are wearing. Bride stands out in white.
However, if you have any other theme party- e,g birthday party and keep a theme- let's say- white and black, as a host/hostess you should adhere to the theme. If you want to stand out, wear a gorgeous white and black but do not wear another color, let's say red, to stand out.
Doing that denotes:
1. You let your friends let down.
2. You treat your friends like an extra in a film and yourself as a main lead.
3. You play petty. You want to stand out over your friends.
4. You cheated your friends.
Moral of the story: Whatever is the theme declared by host/hostess, they should dress up in the same themselves.