DBIx :: Class :: Schema :: Loader ResultSource base class

I use DBIx::Class::Schema::Loaderto create a static ORM in my database. I use the following method to create it and set the base classes for the classes ResultSetand Result, which I can connect to common subsets:

make_schema_at(
'MyApp::Schema',
{ 
    debug => 1, 
    dump_directory => '/home/rob/projects/myapp/MyApp/lib',
    overwrite_modifications => 1, 
    components=> ['EncodedColumn'],
    use_namespaces          => 1,
    result_base_class       => 'MyApp::Schema::ResultBase',
    default_resultset_class => 'ResultSetBase'
},
[ 'DBI:mysql:database=mydb;host=localhost;port=3306','user', 'pass' ],
);

It works like a charm, but I can’t find out how to create a base class for ResultSource. I would like to connect sub to this class so that I can do something like (pseudocode):

$c->model('DB')->source->('Account')->getParentSource('Project');

ResultSourceBase.pm:

sub getParentSource {
     my ($self,$parent) = @_;
     foreach $relation in $self->relations
         if ($relation->identifier eq  $parent)
             return $relation->source;

     return $self;
}

Can someone tell me how to tell the loader to use a base class ResultSourcein which I can connect things like above?

Thank!