if the variables are /set(i.e appear in the variable tab in the script editor) you can use them in any script. That's why it's a good idea to name your set variables something obviously peculiar to either yourself or the script you are working on for example i tend to do my vars something like %btk.varname. This helps stop another script from accidentally changing your variables.
Try to use local variables (set with /var not /set) wherever you won't need the var outside the calling routine.
btk
