Multiple update checkboxes.

Not sure how to deal with this, so I thought I’d get some pointers before I get bogged down.
My insert form has a checkbox group for assigning categories, using 9 checkboxes populated using a recordset and a repeat selection,
This is working fine.

My update form needs to look similar, but with the relevant checkboxes populated, so I reckon I need to use a recordset with a left join, so that I get all of the categories, with the appropriate checkboxes preselected.

Here is a screenshot of the insert page and a mock up of the update page.
I can’t seem to create the desired update page recordset using a nested query.
Is a nested query the right approach to take ?

bit of hand coding required.

anyone who's interested, if you need to retrieve the stored values from a table whilst displaying all of the options, (as you would with a set of checkboxes), you need to create a recordset using a nested query with a left join.

eg,

SELECT CategoryDescription, coalesce(rsselected.CategoryID,0) as categoryid FROM refmessagecategory  LEFT JOIN ((SELECT CategoryID FROM tblmessagecategory WHERE MessageID = 4) as rsselected)  ON refmessagecategory.CategoryID = rsselected.CategoryID