ok
havent gotten use to 2007 charts
but what yo need to do in find the max and min values for the three sets data for x and y
Add these values to both values as seperate plots then select the lines and change the colour to no colour
what it will do is set the max and min value as the same for each axis and align the scales

hope that makes sense

the chart in the attachment dosent have any values so I could set it up