How do I make sure a player spawns in a certain biome?

I'm working on a rather big mod but, I cannot seem to figure out how to make it so the world spawn point is in a certain biome every time a world is created, is this even possible?

Also, if your still confused, I mean for example, if I choose a jungle biome (But, I'll be using a custom biome in my mod) for this, the player's spawnpoint (Only if they don't have a bed or haven't used a /spawnpoint command) would always be in a jungle biome.