I would hope you'd want them seperate too, hahah
I use the "plastic mesh" divider. Consists of one or two sheets of plastic mesh (depends how think you want it to be) and reportfolder-spines. Not the correct term, but it's the removable spines from report-folders. Cost me a couple dollars, at most? You'll have to work with is though, putting stuff against it so it doesn't fall, a good amount of gravel so they don't swim through, and the spines are for support as well.
Found my mesh at walmart, but you can get them at any craft store. Found my reportfolder-spines from Staples, in a pack of 6. Came in different colors. have fun :)