[Typo3] tca configuration of mm table?

[Markus Stauffiger]

Dear Typo3-Users

I have defined a mm-Table in one of my extensions for one of my tables. I'm
able to edit the records and chose records of the other table. Example:
Table of 'event' connected via mm-Table to a table named 'organizer'. It is
no problem to choose the organizers while editing the events. Of course I
want to do it vice-versa, e.g. editing a 'organizer'-record and choosing an
event, otherwise I could just use a comma-seperated list.

$tca[colums] of the event table:
'organizer' => Array (
   'label' => 'LLL:EXT:myExt/locallang_db.php:tx_myExt_event.organizer',
   'config' => Array (
        'type' => 'group',
        'internal_type' => 'db',
        'allowed' => 'tx_myExt_organizer',
        'size' => 10,
        'MM' => 'tx_myExt_event_organizer_mm',
   )
 ),

I think I can not simply put this column-definition into the $tca of the
second table, because typo3 always uses the actual edited table as the
'local_uid', so the entry in the mm-Table is wrong.

How do I need to configure the $tca to work this vice versa way?

I would really apreciate any kind of hint.
Markus Stauffiger