How to assign roles to groups?

We are using TeamCity 6.5.1 Professional and we upgraded because I thought I had read that you could now assign roles to users and groups in the professional edition.  On top of that we also set up LDAP authentication which is currently working.  The question I had was when I click on a group and open up that group's details I do not see a Roles tab or any link to assign roles to a group.  Is this available in the professional edition? Or does it have something to do with the LDAP authentication that we are now using?

Thanks in advance for any help.

Jeremie