It wont give the exact response that you want but you can use the quote api made by ehsankia to do something similar to what you want [CustomAPI] Quote system
People could add their “quote” (level request in this case) and then you could see the ordered list of requested levels with the !quote list (make it !level list or whatever you want)
You can see an example of customizing the command to do what you want in Aaron128l’s post here: Custom Highlight Command?
Alternatively there is a queue customapi listed here: CustomAPI to manage queues