I just purchased a WD My Passport (1 Terabyte) drive that I would like to plug into my router and use as a back up drive AND file storage. I have a mac with windows installed as well as 2 windows laptops and a windows desktop. I know I need at least 2 partitions (one for Mac and one for Windows)...I assume I can backup multiple windows computers on one partition. But I'm trying to figure out if I need to have a third partition for the storage. Or would I use the same partition I use for the windows backups?