Note: this needs reviewing after OG for D6 available.

The [extIC.orgunitmembers] table will be used to write the correct values into the [og_uid] table. But more thought is need first because of the different ways in which ‘orgunit’ is conceived – in some cases as a way of collecting people (og members in Drupal) and in some cases as a way of aggregating resources (e.g. a list of IC members). This means that not all rows in [orgunitmembers] have corresponding rows in [users], so we will have to migrate the data more carefully.

On further review (2/7), I think this will have to be done entirely - or mainly - manually, as there is no obvious way to automate it.