Map Map<Entity, Enum> in JPA 2
@Entity
public class Company {

    public enum CompanyMemberLevel {
        MEMBER, GAME_ADMIN, COMPANY_ADMIN
    }

    ...

    private Map<User, CompanyMemberLevel> members = new HashMap<User, CompanyMemberLevel>();

class Company {
    @OneToMany private Set<User> users;
    ...
}

class User {
    @ElementCollection Set<CompanyMemberLevel> memberLevels;
    ...
}