Non-Marketplace Texture Packs

So currently, we only have the texture, and resource packs that we can buy with money, and with coins. But I think that if when you join a LAN server, or join a friends server, you can have the ability to download the pack and use it. You just can't instantly download it if it came from the shop though, you'd have to still buy it, but if it came from PC or PE, and the pack they used isn't from the shop, then we should be able to download it.