How to create Trust relationship

I am manoj. I am working with Software Company. Today I installed 1 Windows 2003 Server in my network. There are 22 users in this network (all are connected in same network ID). (B CLASS) In these 44computer(system) on the Diffrent network(C CLASS) .Server name is Planetmoi.com. server member all 22 user Access Diffrent network (B CLASS ) IP 44 Computer (Connected witch 48 port switch)
And Access all Data in the network.

But Switch (C CLASS) System 44 User (COMPUTER) Not Access in The Diffrent IP Networking Server Planetmoi.com. Member 22 User not Access.

How to access C CLASS To B CLASS .

Thanks a lot in advance.