If both F and G are closures over x, and you externalize F, and later externalize G, how do you make sure their environments are enjoined when F and G are reifi

If both F and G are closures over x, and you externalize F, and later externalize G, how do you make sure their environments are enjoined when F and G are reified in a different Lisp process? In Common Lisp, what about LOAD-TIME-VALUE? Recursive printing of the environment just to serialize a single function seems atrocious and hazardous.