How to make a Frame scale the X size to the most largest X size in a Scrolling Frame

I want a scrolling frame that can be scrolled in the XY directions.
the scrolling Frame already has a feature that its canvas update to the largest size X but i want the other children X size to reach the end

example:

there are two frames in the ScrollingFrame
one of them is larger in the X size than the other.
i want that other frame to also have the X size of the largest frame