If the timeline is generated automatically the Scheduler should handle cross-border events transparently. You can test it by adding such an event to the main test page:
https://javascript.daypilot.org/demo/scheduler/
dp.events.add(new DayPilot.Event({start: "2015-12-27", end: "2016-01-05", text: "Cross border", id: 3, resource: "C"}));
In some cases moving of the cross-border events may be forbidden. It's in cases where it's difficult to guess how the timeline looks like (a manually-generated timeline in scale="Manual" mode; a mode that skips non-business cells during drag and drop using eventMoveSkipNonBusiness=true), etc.
If it doesn't work in the standard setup, could you please post a config that reproduces the issue?