I have a G5 Imac and a G4 ibook. i want to use time machine, and have one external hard drive connect to both. I could get an external with more than one input (ie, usb and firewire)--does that work? Could i use a usb hub to connect the 2 computers to the HD, and set up different partitions? And what of NAS? i do not want to set up a whole network (we already have one at my office, and i want this to be independent) I have looked for the answer, and seen contradictory replies. thanks!