Can you make a sector that renders the sky texture, without deleting a sector.

[Aquavine]

So when making a stage, I wanted to make a thok barrier, but one of the barriers were inside a sector, and I ended up with a invisible wall instead of a sector rendering the sky. Which made it look extremly ugly, I made a quick presentation of what I want to achieve:

The sector in the middle is a sector with it's own thok barrier, but with deleted sector inside it, and the green patches are regular thok barriers.

My question is, do I have to do it this way, or is there some tag or sector effect that I missed.