Hello CB Experts

I'm new to CB and I'm building up a new site für our firefighters team.

I'm trying to set up the following scenario: The public site shows general information (user group "public"). To get more information, especially about the actual emergency operations, I want users to register and become part of the "registered" user group by entering name, e-mail-address and just basic informations about themselves.

Then I created a child usergroup called "registered crew" for our firefighter crew members. As soon as a crew member registers, an administrator will migrate him into this user group. Now I would like to show more profile fields to only the members of this child group "registered crew", so that the firemen could enter additional informations (rank, training status, firefighters unit...) to their profile, which the normal "registered" users, who are just registered visitors and not members of our firefighters team, don't have.

Is there a possibility or an add-on to CB, that would let me decide, whether certain fields just show up in profiles belonging to members of a certain user group or child user group?

Thanks for your help!
Andy