[NEST Users] Trouble about the spiking time will increase and get so bigger with the simulation epoch increasing.

Deal all, I am recording the spiking time of neurons after every simulation, and I find that the time beginning of every simulation isn't all 0 except the first simulation. So how can I set to recording spiking time beginning from 0 during all simulations? By now I am processing that for every simulation spiking time recording by deleting all the time used before a specific simulation epoch. Hope for your answer,thanks! Enguang