Given enough motivation, talent, and time, anything is possible in JSL.
Another great way to do GEEs would be through JMP's R integration. There are a number of different GEE packages on CRAN, and integrating R with JMP works so well that it might be a better experience (for me, anyway) than "rolling your own" GEE in JSL.
...and I would be remiss to fail to note that SAS PROC GENMOD rates highly in Horton,N.J. & Lipsitz, S.R. (1999) Review of Software to Fit Generalized Estimating Equation Regression Models, The American Statistician, 53:2, 160-169.
Of course, SAS also integrates spectacularly with JMP. There are a number of examples of SAS:JMP Integration starting on my page 590 in the Scripting Guide.
Has there been any forward movement on GEEs in JMP? A release regarding JMP 11 from four years ago said that this was coming, but I cannot find it in JMP13.
I am not adept in JSL and am looking for options already present within JMP or within a JMP add-in.
Thanks for your help!