where clause in dropdown

<img src='https://asprunner.com/forums/file.php?topicimage=1&fieldname=question&id=2740&image=1&table=forumtopics' class='bbc_emoticon' alt=':unsure:' /> Is there a way to filter a dropdown box (while doing a lookup) so several thousand records aren't listed? But filter would be different depending on that record. To explain: say I'm looking up a company, and on this record I know the company starts with da. Ie., David Phillips trucking co. Whereas on another record It might start with Th for Thomas Transportation. If this can't be done, is it a feature you could add? I have around 5500 companies that need to be in the lookup table.

P.S. So far this is a neat program.