External Links to master part

I am making a valve that has multiple pipe sizes that connectto it. The valve body stays the same while the hole/port sizechanges to 5 different sizes. What is the best way to create theparts for these multiple sizes? And the best way to create theAssemblies? Currently I am using one part that has configurationsfor each size, and I am using configurations all the way up throughthe assemblies. I am running into trouble when I have custom valveswhere more then the hole size changes, the assemblies seem to dieand also get confusing? I am having trouble managing all of thisstuff in my current set up. Any suggestions are welcome.SolidworksAssemblies