Solved it by making a loop instead of using gemlist. Sorry for the noise. See attached for a demo of the solution if you are curious or if you might have a better/alternative solution.
I have about 100 spheres I generate with a gemlist which currently display into a gem window. I'd like to instead put them into a gemframebuffer. Is there a way to do this? It seems that gemlist is hardcoded to display in the window? I can think of workarounds i.e. make 100 abstractions of my sphere but that seems clumsy and perhaps inefficient.