I figured out how I'm gonna do it for multis, so anyone that will care to contribute should read this(so far it's still only me lol).
Each system gets its own multicart category, and there will be pages for gallerys of all 3-in-1, 4-in-1 carts etc. BUT, only generic ones, by which I mean, multi's without IDs. In order to have some sort of organization I've decided it's best to have all multicarts labeled under any ID system to all have their own page. So all JY 4-in-1 carts will be on their own "JY 4-IN-1 multis" page etc..
Best I could come up with anyway =p Some other things will get their own pages though like Mario Family carts, or Rockman 6-in-1s and all that.