ODT output Cyclone III HPCII DDR2

Is the ODT output (mem_odt) required? If the DDR2 chip(s) are on-board terminated and not used in banks can the mem_odt input be simply grounded? If the Altera HPC needs to drive it, can it be on another IO bank (at the same voltage)? Would really like to use the two PLL output pins as a PLL output and using ODT gives me one-too-many to allow that.