There are a couple of ways that you could do it. You could run a second fuel cell up front with it's own pump and regulator for the nitrous. This way you can run higher octane for the N2O. Or you can upgrade your existing pump to one of say 250 - 300 GPH to support both motor and N2O. I'm sure if you contacted the manufacturer of the Nitrous kit that you have, they will give you their recommendatios as well. With one pump, one fuel tank/cell your saving weight as well. Good luck!
Rob
Rob