dataridviewcomboboxcolumn / combobox hiding items

[RS]

I have a datagridviewcomboboxcolumn bound to a Funding source table in
database. With time these funding sources may be inactiveted (inactive
flag is set in the table). So when you open up a new form, or an old
form, the original selection should apper, but the user should be
selecting only the active items from the drop-down list, if he choose
to change the funding source, otherwise leave it.
If I populate the combobox with active items only, I get an error
'Invalid value', so I have to pull everything in the combobox. So how
can we prevent user from viewing/selecting items that have inactive
flag set? Thank you.