You may add as many additional fixed or motorized satellite positions as you wish to a Glorystar system. Just request a 4x1 DiSEqC switch option when ordering the system and we will make sure that it is included at no additional charge.
123W would be 24 degrees off axis for a dish aimed for the Glorystar system, so reception of this satellite would be with extremely low performance. You should consider adding a second dish or going with a toridal design dish for receiving satellites with this great of distance between.