A2K need help with list box processing

[Larry Kahm]

I have an Access 2000 database with frmStaff that has two list boxes:

lstMDWGroups - which displays a list of security Groups from the MDW
lstGroupAssigned - which displays a list of Groups assigned to the staff
member

The code in Add mode lets an admin assign a new staff member the appropriate
security groups (multi-select). In Browse mode, the values are simply
displayed.

The client wants the ability to add additional values to the
lstGroupAssigned list and the ability to remove them.

I can use the same code to process an update as I used during Add mode, but
I'm drawing a complete blank as to how to track what was selected for
removal.

Of course, I can't re-write all of the values, because the code that updates
the MDW throws an error when a duplicate value is added.

Thanks, in advance, for your suggestions.

Larry