changing IP addresses

A couple of our people have to move between different buildings in our district and they would like to use their laptops in those buildings to print and get email. We use static IPs assigned to each computer. I realize I will have to give them an IP for each building so they will be able to access the network but is there a way to set up the laptops for several IPs so that when they are leaving one building they can just activate the IP and gateway info for the building they are going to so when they restart the computer in the next building they will connect. I am looking for the simplest way to do this so they do not have any problems. The laptops are running Windows 98se and are not equipped with wireless so they will be physically connecting in each building.