Syncing time on two networked machines

I'm trying to sync the clocks on a Windows 7 (A) and a Windows 8.1 (B) computer on their own, private network by using the command (cmd on computerA):

net time \computerB /set /y

As I expect, this command gives me an access denied error, since the local administrator account on computerA doesn't have permission to computerB.

I would like to set up an account, or allow Everyone or Guest permission on a specific area of computerB, so that this time sync can occur properly. Unfortunately, I can't seem to find any documentation about permissions related to this command, and because of that, I'm working under the assumption that this command will require administrative privileges on both machines.

This network is completely offline, and for all intents and purposes, it's comprised of only these two machines. I would ideally like to have a time sync happen without adding additional accounts on the machines or computers/servers on this network.

Is this possible to do with net time, and if not, is there another way that I can sync computerB's time onto computerA over this offline network?