It's difficult to determine what isn't working without seeing the script. Can you let me know what scripts the buttons call? This may help me determine what is the problem.
Since the main database and external database have no relationship, then there could not be a script run based upon a relationship. I'm a little confused.
However, in your start-up script, you can have a reference to Perform Script in another external database.
It sounds like you need to define a relationship connecting your two tables and then use the Go To Related Record script step to select the correct matching record. You can read up on the different options for this step in the help file.
Note: If there is a chance that there might not be a matching record for every instance in your first file/table, then this script step can produce confusing results unless you specifically test for the absence of any matching records.
Read about GTRR and then post some more info on what you are trying to do and we'll see if we can help you out.
Thanks for your help. I may have a way to do it. As I remember, a start-up script can be specified
for an executable. I created a script in the external database that reads a global in the main database
and sets the record position. It works as expected and as a start-up script, it should do the job.