He was stationed as a guard at northern city-gates. There were fifty guards totally, at each city-gate, appointed to protect the gate from robbers, marauders and thieves. There were two junior commanders at \_\_\_\_\_ gate, each of them commanding twenty-five guards.

Should I use *each* in the blank space or *every*? Personally, I would like to use "every", since "each" is already being used several times. Would the sentence be grammatically correct and appropriate if I use "every"?