Over half of my small office now uses Macs, which is great but our corporate backup system does not cover them. I need to back up 3 Macbooks, 2 running Lion and 1 running Snow Leopard. I can upgrade the SL to Lion if that will help. I have a 1TB USB hard drive to do the job with. This is plenty of space. I have already partitioned it into 3 separate drives so that each of the Time Machines can be done on a separate partition. I backed up 2 of the 3 computers yesterday by plugging in the hard drive and running Time Machine... but now I'm thinking that there might be a better way: a way where all the users could automatically back up to their time machines over the LAN, so that they would back up more frequently and with less hassle. We have a Mac Mini running Lion behind the conference room TV that I could easily use as a server to share this USB hard drive. What do I need to do to get my USB drive and its 3 partitions shared over the network, and what do I need to do to get the 3 users automatically backing up to their Time Machine partitions whenever they are on the LAN?