Multiple Editors with Multiple Gravatars?

Hey there,
I’m hiring some new staff members to my site and I’m wanting them to all have Gravatars that appear beside their posts they make.

The problem is I don’t know how to use unique Gravatars depending on which editor is writing the post.. I can’t have my face for each one of my staff members! 😛

Anyone know a way for each staffer to get their unique pic?
-Thanks
-John