Upwards unbounded scrolling

Hello! I just got Construct2 and it's lots of fun!

Is there any way to enable Unbounded Scrolling, but only in 1 or 2 directions?

I guess you could make the game turn off unbounded scrolling the moment the undesired object(character) strays too far to one side, but that seems a bit hardcoded and forced. Is there any more elegant way?

Also, which variable refers to the layer being Unbounded or Bounded? How can I change that variable from inside the game?

just have a proportion so that the higher the object goes the more the layer or layout scale changes when the object is outside layout