Hi, Kathleen,
Without seeing the score, I'm guessing that the x-head notes all look like quarter-notes, without flags or beams. To let the braille reader know that the number of them in a measure is not a mistake, I'd use the irregular-group sign, preceded by the transcriber-added dot 5. I think you can interpret the straight line as a "slur that does not end on a note," and use the "Let it ring" sign (dots 56, 14).
Cheers,
Larry