Ok, I'll give that a shot.
Is there a way to do an OR statement on the UPDATEQuery
For example
$UpdateQuery->addFilter("calendar_events_id", "=","i", ((isset($_POST["ShiftID"]))?$_POST["ShiftID"]:"")) OR ("something_else", "=", "i", ((isset($_POST["ShiftID"]))?$_POST["ShiftID"]:"")) OR ("something_else_2", "=", "i", ((isset($_POST["ShiftID"]))?$_POST["ShiftID"]:""));