I have a 500 GB external HD that I have partitioned into 4 partitions. Running it on a Dell desktop with a USB cable on XP Home. I use this drive on my 3 machine network at home, mainly for backup and music/photo storage. Before I can access this drive over the network, I have to reset the "sharing" on each partition or it can't be seen on the network. Is there something I can do to allow all partitions to be set to be shared, and only do this once? Typically, I "Safely Remove Hardware" on this drive before turning off the computer at night. Not sure if this is important or not, but thought I would mention it.
Thanks for any insight and advice

Is there something I can do to allow all partitions to be set to be shared, and only do this once?

Try not "Safely removing hardware" and leaving it connected.

Another option would be to switch to a Network Attached Storage (NAS) device (e.g. Buffalo Technology - Network Storage (http://www.buffalotech.com/products/network-storage/), an old computer with FreeNAS (http://www.freenas.org/), etc.) which wouldn't require your current machine to always be on for the other computers to have availability.

Disclaimer: The following has not been personally tested, may work, may not.
To use your existing methodology, a batch file(s) with a series of "net share MyShare=Drive:\FolderToShare" commands might automate the process of resharing. The batch file(s) might even be able to be placed in the root of the drive(s) and an autorun.inf file(s) created to execute it automatically when drive is connected.