Connecting hard drive though router

Thank you for your reply. Yes I can do that ,but it would mean I would have to turn on the iMac or PC. I would like to be able to access the hard drive,mac,PC & live hub without having to move the hard drive around. I could buy a nas which I think will get around this but only if I need to. I just can’t work out why I cannot pick up the hard drive though the router on the live hub like I can on the mac & PC. Thanks