No, to set a users role you have to have the admin role. Authors cannot change or set roles
An important thing to keep in mind is that it isn't an editor who logs in, it's a user with the edit role. Roles don't login, they're just collections of privileges assigned to users.
Is there a standard way to set multiple authors
Yes, give multiple users the author role or higher, a site can have more than one author
a way to make a role an author rather than a single user?
A role isn't a thing, it's just a collection of privileges. The equivalent is hiring the concept of a degree in medicine rather than a person who earned that degree and became a doctor. Be careful of how you word things
I want to restrict groups of people to only edit certain pages (IT department to only edit IT pages, HR department to only edit HR pages and so on).
You've ran into a classic XY problem, where you asked about a problem with your solution, not the original problem. You should ask a new question with just the above paragraph. Be aware that this isn't something you can do clicking around the interface, there will be code involved