Mapping User Roles

I can see you can limit access on role but can you map roles somehow?

Currently users in my external database only get a subscriber account when they login to the WordPress site.

Can I allow some people to be Administrators, Editors, Authors etc whilst keeping some users as subscribers?

http://wordpress.org/extend/plugins/external-db-auth-reloaded/

http://wordpress.org/plugins/external-db-auth-reloaded/