So I have this given: Screen Shot 2014-06-23 at 3.53.01 PM.jpg
and I am trying to fit my data to the graph I have in excel below.
There is only one x-axis; suction pressure. However, there y values are dependent on two variables, discharge pressure and outdoor air temp.

How can I make the data on this sheet:
Screen Shot 2014-06-23 at 3.53.05 PM.png

dependent on both axes?