Hello there, @westcoastoutbuil.
At this time, there isn't a way to give user access particularly to the payroll area only.
You may refer to this article to learn more about user types and permissions in QuickBooks Online.
Also, I'm attaching this article for your reference, in case you want to learn how to add, delete, or change user access in the future.
You can always visit our Help Articles page in case you want to learn some "How do I" steps in QuickBooks Online.
Don't hesitate to post again with any questions. We're always here to help.