next assembly 10 that is configured with the same size seat 24 it is an aspect of the invention to build such a system that includes one or more of the assemblies 10 as described and a similar assembly at a downhole extent of a particular group of assemblies of the system that does not include recess 16 or that the seat created in the last assembly in the group of assemblies is a nonexpandable seat without recess 16 the plug 26 will not pass the seat 24 and hence will hold pressure without release it is this assembly of each group of assemblies that allows for fracturing pressure to be imposed on the open ports of a group of assemblies it should be clear to the reader that not only can there be a number of assemblies 10 that use the same size plug 26 in a system but that the system may also be expanded to include more than one group of assemblies more specifically a full system may include for example four assemblies 10 that use the same size plug at a downhole end of the full system and the downhole most of those assemblies being a nonpassing assembly four more assemblies that use a different size plug than the first four assemblies do larger with.