Create user roles and profiles in Codeigniter using Ion Auth
I would recommend just adding all the fields you need into the meta table and only updating the ones you need per user group. If you need multiple groups per user check out Ion Auth v2.
I had the same problem before, what I ended up doing was building relation tables to handle different groups with different fields. Then I modified the profile() code a bit, to join the additional relation table according to the user's group settings.
I would start off building a relational database.
example:
**volunteers table**iduser_idlanguages**organizations table**iduser_idmissionThen depending on user group, join the table in profile() function.
Hope this helps!