I work in a small office. We have 7 employees in the branch I work at including myself. I was not planning on inviting any of my co-workers. We all get along but rarely do we do things outside of the office as friends. If I invited anyone it would be my boss (the owner) and his wife. Maybe one other co-worker that I am friendly with and his live in girlfriend. What is the etiquette on this? If I invite one do I have to invite all?