Here's another way of doing it. It may not be worth the effort but it's a good mental exercise...
Model the XJ without those extra (compression) forces but add a CUT LONG to your model.
Select a pipe on one side of the XJ or the other, break that pipe into two elements where one element (the one closer to the XJ) is now the length of the XJ pre-compression. Reset the material of this element to CUT LONG (material index #19). Be sure the trailing element is set back to your proper material. Now add CS to every load case name. Check the results.
That "cold spring" will double the length of that cut element. You could even run CS as a separate analysis to see the compression separately.
Make sure your XJ vendor is aware of this pre-compression. It affects the overall fatigue life of the joint.