How can I be 'faster' at this process?

I work at a grocery store in the Grocery department. We have 13 aisles, plus a front corner of the store that has a ton of beer and wine there, plus the endcap displays of all 13 aisles on the front and back sides of the store. Basically, because of the way the company has igone with a new timekeeping system, we are now limited to two employees to block/front and face the store. Meaning we go through and pull 2 of each item to the front of shelf so that when you look down the aisle, everything is in a straight line. If a customer picks up one item, there is still another right there behind it. The problem: My employer only gives us two people to do this at night. They theoretically want us to do it first thing when we come in for the afternoon shift. They basically want more than half of the store straightened by 2 people in 2 hours (one hour for each employee). Well, I usually come in at 3pm and start on the endcaps and perimeter (their procedure - in case the district manager pops in, he walks around the perimeter of the store). I start at 3 and do this all day for my job, basically. Usually nobody else helps me until 7 or 8pm. By that time, the customers shopping the aisles I have straightened have destroyed it again, as if it was never done. It's a losing battle most of the time. My managers seem to think I should be able to straighten 13 aisles in this matter in a manner of 2 hours. Even their fastest employee couldn't get half of that done in 2 hours...he would need at least 3-4. Any suggestions as to how to deal with this situation without causing a problem? How can I be 'faster' if I'm already working as fast as I can?