Thank you raymb1 and Matt Finley for your replies.

After reading raymb1's reply, I realised that I did not ask my question correctly. What I was looking to accomplih in Editable Notation was quarter-note triplets, e.g., 3 quarter notes in two beats.

Based on raymb1's answer for putting 3 half-note triplets on four beats, I deduced to change the song to triplet resolution, and then put a note on the 1st, 3rd and 5th divisions of the first two beats of the bar.
It worked perfectly.

Based on the FAQ (#25) that Matt's link pointed to, I found that it doesn't work if triplet is on beats 2 and 3 of the bar, but it works fine on beats 3 and 4. Also, if for any reason I don't want the entire song's notation to be in "triplet feel", it seems it cannot be done.

Again thanks for the help.

Andy Smith - Chester, NJ