I'm invited to a dinner party but I don't like any of the guests...?!
When I'm around people I don't like I just don't show my feelings and focus my attention on the people I do like and soon you will forget the people you don't like are even there :)
You are going to party because you like the host. Focus on job and forget about everything. If you had to keep quiet its not a problem. Try not to argue or fight with people whom you don't like. So you don't spoil your host party. Try to cheer all the people and host if you got talent to do so. Not everyone got ability to entertain others.
Just pretend for the sake of the host who invited you, and who you say you do like.
Other than that, make an excuse and don't show up.
You can always "break your leg" on the way over only to find out that it wasn't really broken.
Why do you dislike so many people? Go with an open mind and maybe if you get to know them better you will find others you like.
Well, it's free food. So go