Late Game Enchantment (Primarily for elytra?)

An enchantment that when applied to 2 of the same item, you can combine the items to get 1 item with a total durability capacity that's double the original. Its only found in books from end cities, no trading or enchantment table, and only the lowest level can be applied directly from book to item. All higher levels must be obtained by combining 2 items with the same level. It could be called durability, or merge, or something. So you could get 2 elytras, apply merge I books to both, then combine the elytras to get 1 with double the normal durability and merge II. Merge III would have 3X durability and it could be capped at III or IV to prevent abusing it. This could be especially nice for elytras as it can be a pain to have to stop and repair all the time. It can be made rare so as not to be game breaking or be limited to only rarer items like elytras or Netherite items.it can only be found in its lowest level, you will never find a merge II or III book, only I. There's probably lots of tweaks needed to make it viable in game but I think it could be really handy.