According to the script notes, the Pod #1 "the Federation Delegation (Green)" […] Pod #2 "the Vulcan delegation (Yellow?)" […] Pod #3 "the Klingon delegation (brown?)", and Pod #4 the "Earth (green) delegation emerging and taking their places..." Also among the crowd were "the Klingon and UFP Presidents, complete with advisors, retinuies, entourages and attendants." […] "The place looks like the UN Security Council + the Olympics. All color coded..."
The final color coding appeared to more accurately depict the following: Green for Earth, Red for Klingons, Yellow for Vulcans, and Blue for the Federation.
One of their costumes was sold on It's A Wrap! sale and auction, which described the costume as "a mask and wig worn by one of the Khitomer attendees, the mask is dark-gray, molded plastic featuring various textured accents meant to emulate some kind of hardware or circuitry and a mustard-colored open mesh over it. Also included is a curly-haired wig in various shades of brown that falls long in the back and a purple conference sash." 
This flag bearer was seen outside carrying a flag, while leading the Federation delegation into the building where the Khitomer Conference was held in 2293. He stood about the rear of the room along the wall while the conference took place.
According to the call sheet, there five male and five female flag bearers present at the conference.
The name of the race, described as ""Silvertube," an Amazette alien", was directly from the actress. She was shooting the scenes at the Brandeis-Bardin Institute and was chosen to portray the Federation President's assistant. She should play his "eyes", because in an early version the president was blind and she should guide him. However, the scene with her and the President was cut from the aired film. In the finished film, she was only seen in the background, but the cut scene was part of the theatrical trailer.