There isn't a way to disable the solid behavior, but you can move the walls out of the way for those times when you don't want them there.
Create two instance variables like startX, startY in the wall object. Then at start of layout set wall's startX=self.x and startY=self.y.
Then when the player clicks on the other platform, set the position of the walls to something off the layout like
When the player has moved to the next platform, put the walls back in place:
You need to take care that the player doesn't get stuck in the middle of a wall when you put them back.
You also can just move the walls that the player collides with, but it is a bit more difficult to know when to put the walls back.