3pc box in assortment box box

I bought an wall mounting assortment box with several boxes in there. Each of this boxes can be seperated by a small plastic "seperator-card". You can seperate each box up to 3 times. And you got 5 of this "seperator-cards" in packaging. - Did I mention, that you can buy 10pc of this cards for about 3€!? There is no way for me to buy them, cause there are 36 boxes in it.

Because i'm soldering out electrical parts to reuse them, I need a solution to get them sorted. First I "designed" one of these seperator-cards, but then I took the decision, that placing boxes in the box is much more useful. - So I can easily take one single box out, I can resort them quickly and I can place a sticker on it.