Lisp - need a shared namespace variable - sim to VL-BB-Set

I need to be able to share a small amount of variable data between drawings - during the same session of DraftSight, in LISP.  Is there a way to do this?  AutoCAD / Bricscad have the ability to use the Visual-LISP functions VL-BB-Set and VL-BB-Ref which DS doesn't have.  Any other tools?