Add a required field to the 'Post New Thread' template?

[TWood]

Is there a way to add a required field to the 'Post New Thread' form? I want to require users to add a prefix number to all new posts that can be used for search and filter.

Thanks

--------------- Added [DATE]1245859724[/DATE] at [TIME]1245859724[/TIME] ---------------

Is this the type of thing that I should post in the PAID support section? As best I can tell it would require adding a new field to one of the database tables, and some PHP to the interface.