network/sharing workbook

Using a WinXP SOHO P2P windows network.
Excel = Excel 2002, on 1) XP machine and 2) Win98se w/ Excel 2002.
1. While the ‘master’ file resides on the XP machine, setting up the file for full access sharing, is it possible for the file to be updated by the 98 machine and have the update reflected back to the XP machine for “master file” updates?
2. Is There an easier way of currently updating the files, other than haveing the remote unit make the changes and then closing the program and then re-opening the file to publish the updates?