Bridging Networks

I have w2k LAN using 90.0.0.1/200 ip addresses. I have installed W3K LAN with 192.168.100.1/200 both are using 255.255.255.0 masks.

I have exchange 5.5, Oracle dB server, satellite connections using 90.x.x.x. My intention is to chagne class A address to calls C address but cannot go to each machine and simply change the IPs.

I was planning to brindge both the networks and pull down each Wks one by one from old to new IP scheme, alowing both sides to access email, DB and internet without diconnecting them for days.

I would welcome any suggestion and the procedure to bridge the network.

Thank you in advance for your support