server in a p2p environment

We would like to implement an centralized server solution in 4 satellite offices that are currently set up as 4 seperate peer 2 peer workgroups. A Windows 2000 server will be placed in one location and three other offices will be connecting to the main offce for file storage. Almost all of the clients are Windows 98SE. Given that they are in individual workgroups, what is the best way to have them access shares on this new server.