I have an external hard disk which I share with my girlfriend, so it has two partitions: One for her and one for me. And I would like that when I plug it to my computer, only *my* partition is mounted automatically and I would not even like to get the window asking whether I want to mount my girlfriend's partition too. And vice-versa, when my girlfriend plugs it to her computer, that only her partition gets mounted and she doesn't get a window asking whether she wants to mount my partition.

Thanks in advance.