Say I have a .csv with information:

I have "System Serial #", "Site", and "System Type" as dropdown fields in my "Issue/Bug" issue type in my team-managed project. The available options in those dropdown fields span the options listed in the .csv.
I want to automate the updating of "Site" and "System Type" by entering the "System Serial #" during issue creation using information I have in a .csv similar to the above picture. I would rather not make a new branch rule per "System Serial #" and update information accordingly.
Let me know if I need to make clarifications.