How to use NTP with offset in domain?

[PliotronX]

Hey guys, I'm used to fixing time offsets and correcting clock sync in domains because of the criticality of syncing time for Kerberos but an odd request from an attorneys office wants their time five minutes early. My googlfu is only turning up scenarios where users want the offset fixed (understandably). So how to keep the DC synced with internet time so it doesn't drift but apply a -5min offset is what I'm wondering. Anyone done this? TIA