City Select Q for those with a double seat already.

Does anyone know if the city select can support both the extra seat as well as the glider board? I can't find the info on it anywhere. Figured it would be faster to ask you ladies than email Baby Jogger. I will have a 3.5yr old on the glider board, a 1.5yr old and a newborn in the seats (oh and I guess a carseat...) that seems like an awful lot of weight