You could just define one or two steps in PrePoMax, use File —> Export to write an input file, open it in any text editor, copy, paste and modify the lines between *STEP and *END STEP (in this case, just change the *CLOAD magnitudes and degrees of freedom if needed). Of course, you could use some custom script to automate this. Once you have the input deck ready, submit it using standalone CalculiX as explained here: Using standalone CalculiX
After it completes, you can just use File —> Open to read the results from the .frd file generated by the solver for postprocessing in PrePoMax.