I have a project that I am working on and I have a common drive assembly that we use to retrofit existing equipment.  I will need about 30 different configurations of this assembly.  The only difference configuration to configuration is the length of an ACME ball screw.  the problem I am having is when I change the configuration in a assembly it automatically updates all of the drawings and assemblies to the current configuration. what am I doing wrong and what can I do?

thanks

Brad K