Random Text Cycle Script

I got this script from this site and was wondering how I could limit the character range to specific characters…like only the letters in the word it’s going to form. I tried editing it so ((x>=69,75,82,85) but it doesn’t seem to work.

onClipEvent (load) {
go = true;
onClipEvent (enterFrame) {
if (go) {
x = random(85);
if ((x>=69) and (x<=86)) {
this.letter2 = chr(x);
if (x == 85) {
// replace [number] with the number corresponding with the first letter in the word you want.
go = false;