I'm just asking whether it is possible to have a number of sub assembly with a number of configurations that all be altered from a master assembly. Example, two different length chassis (with a extra crossmember in the longer one), another sub assembly to have a choice of axles and another sub assembly with different suspension systems. Some of the configurations would not be able to be used with certain configurations. Would it be possible to have it so that the master assembly can select alter these configurations some something like the configuration publisher. Sorry if that is not every clear but I will be happy to try and explain this better if needed.