Redefine AXIS2 to change the range of values and suppress all axis elements. Setting all the label and tick mark options to NONE and assigning a line style of 0 removes the response axis. NOPLANE removes the 3-D axis plane. Specifying ORDER= makes all the graphs use the same range of values.

axis2 order=(0 to 250 by 50)
label=none
value=none
style=0
major=none
minor=none
noplane;