Password Protect Map Network Drives & Home Folders

Hi,
Having a little trouble with protecting Mapped network drives within XP Pro. I have two separate partitions (Shared) and two groups and only want each group to be able to access there drive and within each drive I would like the users to have a personal folder(or My Documents Folder that is mapped to that partitioned drive)which can only be accessed by them, with permissions or password.
Could anybody please help with some instructions it would be much appreciated.
Thanks