Hmm i really like your question made me think for a second.
I know with TextureButton there exists a disable property but with TouchScreenButtons you might have to set
_input to false. also TextureButton has the
_gui_input() signal which guarantees only that button is being pressed
But if it must be a TouchScreenButton first connect the on_scroll started/exited signal to a script:
var box = Rect2(rect_global_position, rect_size)
for child in $VBoxContainer.get_children():
var centre_point = child.global_position + (TouchScreenButtonSize / 2)