How to update DFF at project level using class code selected by user while creating project

Summary:

Have a requirement wherein based on location selected by user which is coming from class codes , a default DFF value should be updated .

For example if user selects locations as Brazil , the flexfield Division as South America should update automatically .

We cannot use bind variables to fetch the system values dynamically, what is the alternate option for the same

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):