Direct/Connecting Service 

Recently I have been adding (and subtracting) destinations from the United Airlines domestic and international lists after searching through SFO's and United's websites for destinations. However, it seems that while Bangkok (plane change at Tokyo-Narita) is included, Brussels (plane change at Washington-Dulles) and Munich (plane change at Chicago-O'Hare) are not. Also, service to Ho Chi Minh City has a stop at Hong Kong. Is there a standard for inclusion or exclusion? If there is, what is it? Thanks.