Laser engine describes how you can do it manually. If you want to do it in the auto mode... select part properties after choosing the parts you want to give common cut in the make sheet window, tick enable common line cutting, and then choose the different techniques employed for common line cutting, ie part grid, ala logic, ala logic pair by rotation,...each one gives a different result..one limitation i've found is that if you use common line cutting for different parts, auto joint creation suffers. Do give it a try.