How does one unbundle?

My biggest deterrent from simming, and the reason, apart from learning curve, that I rarely complete a project, is the horrendous mountain of downloads I must wade through whenever I attempt to work on something. My game currently will not load. I do have nice tidy subfolders, but this is hardly enough. Do any simmers outside of MATY have knowledge about assembling and more importantly, disassembling bundles like the CS and LS build/buy bundles? I know there are MaryLou/Numenor extractions that exist, but I also know they are not of the same quality as the MATY ones. Some of the content within the bundles is among my favorites, but much of it is redundant and useless to me (slightly darker or dingier versions of BV floors, 20 variations of a wall with wear and tear in different locations, etc.) I've not found any tutorials on how these bundles work. They are organized, I think, just like the official game files, instead of resources having a private ID number of all Fs like in custom files, the resources have an identification number that groups them together. Years ago I tried to rip the thing apart and the resulting files broke all contents so I had to revert to the forced "all or nothing" bundle. Any words or links are appreciated.

Thank you.

I think that the best way is to clone new objects and then add in the resources, so that is the first thing - what do you want from the bundle.

Well, too many specifics to list, and some of that has yet to be determined. I definitely want all the fences but I only need maybe around 25% of the CS walls and floors... I would scour MATY for individual items if I knew for sure they were final versions. If I can't trick SimPE to load the file as if it were part of a stuff pack or such, I guess it will take some time to clone everything and replace the resources, just to have things not bundled.