Re: I need some help...
For this to work correctly, you're not going to want to use a gateway at all. I've had nothing but trouble with machines using two default gateways. Windows has a very hard time routing traffic over two gateways. Here is what I would do.
1) Install the cables to the second NIC
2) Connect the cables to your switch
3) Enable the ports on your servers
4) Configure IPv4
IP Address - 192.168.50(whatev).X
Subnet - 255.255.255.0
Gateway - BLANK
DNS Pri/Sec- BLANK
This will provide direct communication between all of the servers, but not to the outside world on that interface. This will be the most fool proof way of doing this. Otherwise you're going to have to set static routes on each of your servers for the secondary interface and routers to make sure that you don't create any loops. A big pain in the ass.
Again, this would be my "take a few hours to tide me over" plan. If you are going to be moving to multiple buildings it becomes more important than ever to have best practices in place. This means DCHP and separate subnets. Migrating to DHCP can be done gradually and with little downtime if you have the ability to assign VLANS per port on your switch.