The system is merlin legend R6 with two T1s and other 408s. Current pools are 70 and 690. We had tried to create a third group 600 or 691 with PC SPm for 24 channels but it did not work. We had verified that 890 - 899 are not used and tried to use them, but still did not work! Anyone had this experience before or know what we are missing? Help!