I have a server (Yes, i have it) with has these world: 1. Lobby 2. Crate 3. Skyblock - is of user a - is of user b - ... 4. Creative 5. PVP (1-5) 6. Skywars I want to make world number 1, 2, 3 has same inventory and the other is different. Nope, you can't. Because every Skyblock island is stored in different world. OK, that's my request
I'm not sure I understand the request. You want the same inventory for your Lobby, Crate and all of your skyblock worlds?
If you have access to the SkyWars source code, I would add a function that adds the new world to the conifg.yml. In my opinion, this is the easiest way to do this
Try to use google.com, this is a really useful website I assure you https://github.com/BlockHorizons/PerWorldInventory you can buddle inventories of worlds (so basically you share the same inventory with example pvp 1, 2, 3, crate world has a different inventory and lobby too). He explains everything in his config.yml