Nothing simple, but it's not too difficult to do yourself.
Depending on what kind of RowSource you're using. For a
table/query, just use a Select statement that filters out
the undesired row. As per your post's subject, for Call
Back type, add some code to your procedure that skip the
undesired data.
If you're using a Value List, replace it with a table and
use a Select statement instead.
If you'd be more specific, I could try to be more helpful.
