Create a calculation field that is Left ( LastName ; 1 ). Then sort by this field and have a sub-summary part to separate the various letters maybe with a Big capital letter of each letter of the alphabet or whatever. Is that what you are looking for?
Or do you want to be able to click on a letter, which will then show only those people whose name begins with that letter? If so, you could have 26 small buttons, one for each letter. When user clicks any of the buttons, it runs a Find script with the letter as a parameter, something like:
Enter Find mode
Set Field [name_field; Get (ScriptParameter)]
I'm not actually advocating this approach, as it (obviously) involves a lot of repetition of buttons. Maybe consider using a filtered portal, with a "spotlight" style search box?
Thanks so much, I have made the changes and they work perfect. Thanks again