Can only "some" users in an organization be upgraded?

Can only "some" users in an organization be upgraded?

We have a sales force that will need to be on the "Pro" version of Zoho, but most admin staff are fine on the standard free version. Can I have sales staff on the "Pro" version, while the balance of the staff use the free version? That way everyone has the same database for contact information, but the sales people and their managers have more functionality in the "Pro" version.