Astr0nite

I'm trying to make a custom mini game that involves going to the nether and end however I want to make it so that every game there is a brand new world for the nether, end, and overworld. I did some testing and for some reason when I create a new overworld in multiverse, strongholds don't appear. I made sure that structures are allowed but it still isn't working. Is there any plugin that can be used to solve/fix this?