we are PCB factory, and some days ago, i got a gerber from my customer, and his design of the board need drill 1-2, 2-3, 3-4, 4-5, 5-6, 6-7,7-8 and then 1-8. how can we do like this? since when we drill 1-2, we must have lamilate the 1 and 2, so i think then to frill 2-3 will be cann't do, at least, our factory cann't do like this. so i want to know is the design reasonable?