Ah that sounds more complicated than it looks - I was hoping it was like in Hey Joe where you add a note in as you strum and it gives it a little hightlight
You can absolutely do it like that.
You can also extend the 3 note thing and make a little loop of the notes:
F - B - D - F or B - D - F - B - D - F etc around once, twice, several times.
You have to get the timing right to start the little riff motif.
It will vary depending on whether you start on the F note or start on the open string B note.