Players Not Spawning in Exact Same Place

I am using Essentials to assign respawn points for different groups.

Unfortunately, there is an issue. The respawn point for guests is within a box that is super tall and wide. Somehow, when they join, instead of being placed in the proper spawn, they are placed on the roof of the box every time.

IOW:

If you do /spawn as a guest, it takes you to the middle of the guest box.
If you join for the first time as a guest, it spawns you on the roof ABOVE the spawn point (Even though the box is super tall)..

I tried "ExactSpawn", but that interferes with Essentials and also does not allow custom spawn points per group.

ANYONE?

 

The spawnpoint of the original minecraft server shall put the player _always_ on the topmost block.

 

Any way to fix this?

 

Make a plugin that checks if the user is new, if so: teleport them to a specific place.