Never having built a dust collection system, i have a couple questions (I'm thinking others may have the same questions), so I ask: Are remote blast gates normally closed, and when activated they only open to the machine being used? Or is the system usually designed to open one of the "main arteries" and all the the "capillaries" belonging to it would be opened? For instance: If I have a main duct feeding to say a bandsaw, RAS, Edge Sander, drill press and a chop saw - would one gate open them all, or does each machine have its own gate and duct. Thanks