Checkbox to Update Join Table

[hangglide]

I have a "permit" table and a "permittype" table linked through a many-to-many join through "permit_permittype"

Currently I have a form with an embedded subform that allows me to select multiple permit types for each permit and stores the info in "permit_permittype".

There are over a hundred different permit types but we have found that some are used frequently and we would like to put a few check boxes on the form for individual cases. This would prevent specific types from being overlooked by the user (important for later queries). For example permit type 404 is used regularly but the user might not think to scroll all the way down the list in the subform to select it.

The question:
How can I get the checkbox to write back to "permit_permittype"? EG A checkbox to indicate if the permit is a 404 permit.

Anticipated later question:
If the user does scroll down and select the permit type, how do I get the corresponding check box to update and appear checked (and vice versa).

Thanks in advance.

Leo

Also if you have a suggestion for a better approach that is fine too.