How to enable some segment of accounting strings for update

Summary: We have 2 sets of users.

For one set- we want them to update some segments of the accounting string while raising Expense claims

For 2nd set- we don't want them to update any segment of the accounting string while raising Expense claims.

How can we achieve this? What role privileges can help in achieving this?

Content (please ensure you mask any confidential information):na

Version (include the version you are using, if applicable):26B

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