Buildable Bridges
This is is more like a bug, an expensive bug to make buildable bridges between tower, and unlike the default sky bridge, rooms can be build.
I found this method by accident while trying to maximize the benefit of balcony.
I hope the dev make similar feature in future, and not remove this for the moment.
Steps
Step 1
Build 3 level of floors or above.
Step 2
Build balcony below the “bridges”, due to obvious reason, balcony cant be adjacent to another balcony.
Step 3
Demolish the balcony, and build more balcony to fully cover the entire region.
Step 4
Continue until you get your “bridge”.
Beware you can not build room after this is done since room must be build ontop of another floor, build the room first before making a giant hole in your tower.