Change data table of the DataGridViewComboBoxColumn-cell only for the new row ?

The existing data contains values that are not allowed to be selected for new records. If I bind the whole combobox-column to the reduced dataset I get errors, as some old value keys have no counterpart in the reduced dataset comboboxbox.
Is there a way to use the combobxcolum but to change the combo box for the new record row. If no, then I can add combo box cells to each row with the right selection.

Nono!

Thank you! I accept a "no" for my first question, but is the second no for my planned alternative solution?

No the second no was because "No" is too short a reply to be accepted by the editor! I hadn't really considered your alternative but now I have it probably would get a 'no'. Is it necessary to view the records that have the invalid entries? If not then I would recommend you create a DataView to exclude them altogether from the grid. Otherwise, you'll have little choice but to create some kind of validation routine as insurance against anyone adding a record with the invalid choices (or simply bring all the records in the database up to date with regard to this column).

Ok, now I've just learnt something about DGVs that might suggest a way that you could do this using a customised cell type, I may have to have another think about this. I'd still prefer the data to be consistent but other possibilities do now arise.