Ben is correct, and I'll go further: In ALL your models, the default condition should be all CS's, datum points, axiis, and planes, should be hidden, along with layout curves/geometry and that status should be saved. This is best done in your start parts. Then in your layer tree, you can selectively pick ONLY the models who's CS's you want to see. Even better, be aware that for almost anything, even if the CS is hidden via it's layer, you can still pick it from the MODEL tree. for instance, if you're inserting a part into an assembly, and want to constrain CS to CS, you can pick both CS's via the split model tree windows. Oh, and if you only want individual model layers shown, make sure you have the option "No Submodel Layers" checked. You must dig into the layer tree and show them by individual model because if you have "All Submodel Layers" checked, that's exactly what you get.
There are threads here about "rules-based" layers, find them and make your layers like that in your start parts. A presentation .ppt file called "Take Time to Obey The Rules" is linked in several of the threads, and is an excellent source of information. I used it to create my layer structure.
