NETWORKING: IPs & Shares

how can one configure windows 98 and XP machines to operate on the same network with different IPs and internet DNSs but the same workgroup.

I have an organisation with 95 machines with 50 PCs on the 192.168.1.* subnet 255.255.255.0

Then the other 45 machines on 192.168.250.* subnet 255.255.255.0

They have different DNS addresses for internet browsing.

I need to share files and printers for all machines instead of the current setup where the print server has two NICs to serve both groups.