If a card is in the second range, punch the second hole instead. Now make another punch in each card to indicate where in the range that card falls. Y ou might create one index card for 1 through 15 range, and a second index for the rest. S o if you want the 19 category, check your index card. It should say to put a nail in the 2nd hole, and from that shaking, put the nail in the 6th hole.
T here s a limitation to consider.
You can t have single card that has holes in both the 1 to 15 range, and in the 16 to 30 range to boot. You should be able to arrange your categories so that s no problem. If you just can t, then use one of your spare holes for a new, combination category. You can double it to 72 easily. Your first two holes are your super-index.