I'm a little bit stuck on a query, I want to get a range of records where the first letter of the field is between A-C and D-F ... A-Z,

I've tried the between operator but find that records with the last letter of the range are omitted. No problem I thought just extend the range to the next letter but what happens when I get to the letter Z?

This is the query I'm using:

FROM exhibitors WHERE exhibitors.program BETWEEN 'A%' AND 'C%' ORDER BY exhibitors.program
Is there another way to include every record in the range?