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://ww.wp.xz.cn/extend/plugins/external-db-auth-reloaded/

http://ww.wp.xz.cn/plugins/external-db-auth-reloaded/