Unfortunately there is no quick solution other than using two Schedulers. However, this is just a workaround and may not work in all cases.
<div id="dp1"></div>
<div id="dp2"></div>
<script>
var dp1 = new DayPilot.Scheduler("dp1");
dp1.init();
var dp2 = new DayPilot.Scheduler("dp2");
dp2.init();
</script>
Then you need to synchronize the scrollbars using jQuery like this:
$(dp1.nav.scroll).scroll(function() {
dp2.nav.scroll.scrollLeft = dp1.nav.scroll.scrollLeft;
});