How I think it will work.
The fermentation tank is nearby and a silicone tube is connected to the bottom valve, or is simple dropped inside the tank. The conveyor belt moves the bottle to the filling robot, while a limit switch counts the number of bottles going by. When two bottles are in position the conveyor belt stops and the robot lowers the arm, pump starts and solenoid valves open. The beer is pumped through flow meters before going through the solenoid valves and into the bottles. When the flow meters have detected the correct amount of beer the solenoid valves closes, pump shut off and arm lifts back up. The conveyor belt starts again and brings the two full bottles further down while the limit switch count the next two bottles and repeat the process.
Another great feature would be a self cleaning and sanitizer program, where Star San sanitizer or detergent is simply pumped through in a loop.